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North America Transport Air Conditioning
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1. AVT3H NYA dvA3 9814 Ra 9134 803 SrG2 3519 4 35070 di oe NIVA 79 390 qavod 31907 ONDI va AT 79 MO1 ENI HOIH 3 CNOI 1504430 val 7 1V3H 4 410 1V3H I 1 1 av ai 1 1 VI 272 017002 4 40 4 35010 7005 210 1 01 00 amp 3514 9 390 AV UM oza lo 440 98 58 1222 1 Lo SWov AT 3 9226 Wann 820 lt 1 5 42 12 09 Figure 5 41 Wiring Schematic Control Circuit 68RM35 604 71 87 T 302 FLOOR BLOWER SIGNAL 172 173 Kis JP6 JP6 C INSTALL UV2 FOR OSK COMPRESSOR rf k5 163 164
2. 3 1 3 1 SELE DIAGNOSTICS eerie Bea aed werd dead m 3 1 3 2 SYSTEM ALARMS X e dee be xe ee 3 1 3 2 1 Alam Codes ue ane rr daca LI eq uel vest unb 3 widen Mara 3 1 3 2 2 cce oa ieee at ai a ea D 3 1 32 3 Alarm 3 1 3 2 4 a bbs EU doit a 3 1 3 3 TROUBLESHOOTING 2 2225 Rhe DLE a 3 1 3 3 1 System Will Not ply aa EE RUFI DE 3 4 3 3 2 System Runs But Has Insufficient Cooling 3 4 3 3 3 Abnormal 55 5 gate nha e lu 3 4 3 3 4 Abnormal Noise Or Vibrations 3 4 3 3 5 Control System Malfunction 3 5 3 3 6 Evaporator Air Flow Or Restricted Air Flow 3 5 3 3 7 Expansion Valve 3 5 3 3 8 JHeating MaltunctOn aad AC eH a 3 5 cic sale On RE alai OR ACER c aa ataca 4 1 41 MAINTENANCE SCHEDULE
3. 4 1 4 2 SUCTION AND DISCHARGE SERVICE VALVES 4 1 43 INSTALLING MANIFOLD GAUGE 5 4 2 4 3 1 Installing R 134a Manifold Guage Set 4 2 4 4 PUMPING THE SYSTEM DOWN OR REMOVING THE REFRIGERANT CHARGE 4 3 4 4 1 System Pump Down Low Side Repair 4 3 4 4 2 Refrigerant Removal From An Inoperative Compressor 4 4 4 4 3 Pump Down An Operable Compressor Repair 4 4 4 4 4 Removing Entire System Charge 4 5 4 5 REFRIGERANT LEAK CHECK m RUPEE heb eg be RE 4 5 46 EVACUATION AND DEHYDRATION 4 5 4 6 1 General ee UE a ge OP UR ak 4 5 46 2 Preparation rtr ae a Peed 4 5 4 6 3 Procedure for Evacuation and Dehydrating System Triple Evacuation 4 5 4 6 4 Procedure for Evacuation and Dehydrating System One Time Evacuation 4 6 47 ADDING REFRIGERANT TO 5 5 4 6 4 7 1 Checking Refrigerant Charge 4 6 4
4. 4 13 Figure 4 16 Condenser Fan Motor Removal 4 14 Figure 4 17 Evaporator Fan Blower Removal 4 15 Figure 4 18 Reheat Coolant Valve Assembly 4 15 Figure 5 1 Wiring Schematic Legend 5 2 Figure 5 2 Wiring Schematic Control Circuit 688 35 104 40 5 3 Figure 5 3 Wiring Schematic Power Circuit 688RM35 104 40 5 4 Figure 5 4 Wiring Schematic Control Circuit 68RM35 104 41 5 5 Figure 5 5 Wiring Schematic Power Circuit 68RM35 104 41 5 6 Figure 5 6 Wiring Schematic Control Circuit 688 35 104 42 604 56 60 76 5 7 Figure 5 7 Wiring Schematic Power Circuit 68RM35 104 42 604 56 60 76 5 8 Figure 5 8 Wiring Schematic Control Circuit 68RM35 104 43 45 604 61 78 88 5 9 Figure 5 9 Wiring Schematic Power Circuit 68RM35 104 43 45 604 61 78 88 5 10 Figure 5 10 Wiring Schematic Control Circuit 68 5 604 41 5 11 Figure 5 11 Wiring Schematic Power Circuit 68 35 604 41
5. 2 2 Figure 4 1 Suction or Discharge Service Valve 4 2 Figure 4 2 Manifold Gauge Set 4 2 Figure 4 3 Manifold Gauge Set 134 4 2 Figure 4 4 Low Side Pump Down Connections 4 4 Figure 4 5 Compressor Service Connections 4 4 Figure 4 6 System Charge Removal Connections 4 5 Figure 4 7 Checking High Pressure Switch 4 7 Figure 4 8 Filter Drier 4 7 Figure 4 9 Liquid Line Solenoid Valve 4 8 Figure 4 10 Thermostatic Expansion Valve 4 9 Figure 4 11 Thermostatic Expansion Valve Bulb and Thermocouple 4 9 Figure 4 12 CompreSsOrS i sioe een REESE REL HK ERA E d us 4 10 Figure 4 13 Removing Bypass Piston Plug 4 10 Figure 4 14 Comhpressor Clutch a a ERI HER RDUM a ri 4 11 Figure 4 15 Transducer Terminal Location
6. O HOIH 5 7 302 Figure 5 6 Wiring Schematic Control Circuit 68RM35 104 42 604 56 60 76 12 09 3A gt FLOOR BLOWER SIGNAL JP6 J oy gr e 058 P6 JP6 gt 1B A C FAIL DRIVER CONTROL MODULE CB1 154 e 1 e4VDC 1 87 98 62290 Figure 5 7 Wiring Schematic Power Circuit 68RM35 104 42 604 56 60 76 T 302 5 8 12 09 NULLVOIddV 22 3 11941913409 CAVO 91907 NOILVIINdd 303 NOILVXNSI ANOO N3dWnr 08904 21907 8 Wiring Schematic Control Circuit 68RM35 104 43 45 604 61 78 88 Figure 5 T 302 5 9 12 09 7 15 18 FAIL DRIVER CONTROL MODULE 167 CHO e 1 E s O 424VDC 1 87 98 62378 Figure 5 9 Wiring Schematic Power Circuit 68RM35 104 43 45 604 61 78 88 T 302 5 10 12 09 avoa 31907 6 3515 9 35010 9 d MI d 2v ve Figure 5 10 Wiring Schematic Control Circuit 68RM35 604 41 T 302 5 11 12 09 IC FAIL DRIVER CONTROL MODULE CB1 150 2 1 87 30 98 62045 Figure 5 11 Wiring Schematic Power Circuit 68RM35 604 41 T 302 5 12 12 09 d ex
7. SCH 100 20138 OLISCNEVIC NCSS3208 08214 3Shi d 35010 90 e 9 2 viva lt gt dS 14611 gt 22254 1804 SSILSONOVIG 1 1 Lg FOLINS 1681 150 INSA 7009 1 QUVOE Aaa SdH 102 104 3 18V2 NO8EIE aavog 21907 O 1812 T 2812 014005 4084 4 45019 OLFODE 3Shi d 40 4015 8 Gala 039 0814 039 Ped umm 1814 13533 MAM 5 3 amp 9 1O 909 vad ald quo T TR 13534 WONW TL ea 909 583 8814 049 T eus 20172 21901 NO YOLOSNNOD QuVOS NO MOIO3NNOO df NOILISOd HOIO3NNOO Z SIONA 08 38 4 SOLON
8. 929 us 55 0 045 060 959 7 057 076 974 Las 3 un 72 4 199 137 302 Temperature F Bar 2 pum 332 233 2 351 247 2 401 282 2 455 320 3 574 4 04 64 1 451 711 500 787 553 867 610 114 0 8 01 124 2 73 135 0 49 146 4 158 4 1712 1846 198 7 213 6 229 2 245 6 Oy A By ul ola O rR O 81 1976 5 4 alo 10 10 0 115 ele w N 0 5 0 125 0 5 0 5 3 3 4 4 5 5 6 7 7 8 9 1 1 1 1 1 1 1 1 1 0 5 1 3 45 5 51 2 57 4 64 1 71 1 78 7 86 7 95 3 104 3 114 0 124 2 135 0 146 4 158 4 171 2 184 6 198 7 213 6 229 2 245 6 262 9 281 1 Oy 3 BY BY BY GW NINI NI NI FI 9 53 96 42 90 43 98 57 19 86 56 31 0 09 0 92 1 80 2 73 3 70 4 73 5 80 6 93 8 13 9 37 gt 12 09 SECTION 5 ELECTRICAL 5 1 INTRODUCTION This section includes electrical wiring schematics covering the models listed in Table 1 1 For applications with OEM supplied operating switches the switches are wired to the Logic Board connector 3 as shown For units w
9. z T C1B A C FAIL DRIVER CONTROL MODULE 167 15 e 1 Po Q9 04000 87 98 03232 Figure 5 42 Wiring Schematic Power Circuit 68RM35 604 71 87 12 09 5 43 T 302 1 NOILVSNOTINOD 21907 pomme 6 DANDI s 1193 BIVNROTH 98 03272 Figure 5 43 Wiring Schematic Control Circuit 68RM35 604 90 92 12 09 5 44 T 302 CB 1504 24 ALTERNATOR C82 40A swe gaS i JPS 5 SPS BOOST PUMP SIGNAL BPS 98 03272 Figure 5 44 Wiring Schematic Power Circuit 68RM35 604 90 92 12 09 5 45 T 302 NDIIVMODI3NDO JIN 5908 21901 dio loas L 2 2 Poo 98 03273 45 Wiring Schematic Control Circuit 68RM35 604 91 94 Figure 5 12 09 5 46 T 302 CB 1504 I 677 24 V BATTERY C1B A C FAIL DRIVER CONTROL MODULE C3A BLIVER SIGNAL 154 21 Pi 24VDC 87 30 98 03273 Figure 5 46 Wiring Schematic Power Circuit 68RM35 604 91 94 12 09 5 47 T 302 rsrWiswr NDILVNOSIJNDO N3dWnr BNDH 21907 C 803 NIVA
10. 4 10 4 14 1 Shaft Seal Reservoir n sai a ai aa ie Ra a a 4 10 4 14 2 Removing the Compressor 4 10 4 14 3 Transferring Compressor Clutch 4 11 4 14 4 Compressor Oil Level 4 11 4 14 5 Checking Unloader Operation 4 12 4 15 TEMPERATURE SENSOR CHECKOUT 4 12 4 16 PRESSURE TRANSDUCER CHECKOUT 4 13 4 17 REPLACING SENSORS AND TRANSDUCERS 4 13 4 18 REMOVING THE CONDENSER FAN MOTOR 4 14 4 19 SERVICING THE EVAPORATOR FAN BLOWER MOTOR ASSEMBLY 4 14 4 19 1 Removing and Disassembling 4 14 4 19 2 Routine Examination and Cleaning 4 14 4 19 3 Brush Replacement e EA 4 14 4 20 SERVICING THE REHEAT COOLANT VALVE 4 15 4 20 1 Reheat Coolant Valve Malfunctions 4 15 A 20 2Replacing the RI a se ce had Oe grad ed 4 16 4 20 3 Replacing the Interna
11. WEY 43345 WOIVHOdVAi 88858384 5 AVIS HOlvHOdVAT SUQIOW ANOO 10151534 ONIddOHT 34155384 4198 30010 5 z 03345 W3SN30NOO CNO READ 2 535439405 MOSSZMdNOO HOLT Bl E AVI34 H3SNXINOO LINDT 2 NOLON 15008 5 5 FUNLVYIINSL IN3IEWV 8 98 62067 Figure 5 19 Wiring Schematic 68RM35 604 46 12 09 5 20 T 302 131191541 199 91 3409 N3dWnr 9908 21907 S S 5 4 35010 4080 4 N3dO 1002 avoa 21907 IVAH dNV OT Figure 5 20 Wiring Schematic Control Circuit 68RM35 604 47 T 302 5 21 12 09 2 v C1B A C FAIL DRIVER CONTROL MODULE CB1 150 2 1 4 1 87 30 98 62156 Figure 5 21 Wiring Schematic Power Circuit 688 35 604 47 T 302 5 22 12 09 NOILIVAMOSIJNOO N3dWnf 02908 21901 3 IND 35010 450 GB n lt 4 sim 1VNOLdO TWNOLLdO Figure 5 22 Wiring Schematic Control Circuit 68RM35 604 48 T 302 5 23 12 09 A C FALL SIGNAL GRD BOOST PUMP 98 62215 Figure 5 23 Wiring
12. ole aa E VERE Te VY LIST OF ILLUSTRATIONS EIST OF TAB RO TW Ta DESCRIPTION 5 3535 he rg ERRORES ERE RAT REA 1 1 LL INTRODUCTION so 044 NR ba 1 1 12 GENERAL DESCRIPTION iste re Rc een e n o t 1 1 1 2 1 Air Conditioning 1 1 1 2 2 Condensing System ias eer tme ere ee exe 1 1 1 2 3 EvaporatorSystem a cese ex seen xk aed 1 4 1 24 Compressor Assembly de ati ai daca 1 4 125 Fresh Air Connection RES SC DAR a 1 5 1 2 6 System Operating Controls And Components 1 5 1 3 RELAY BOARD 12 00371 00 544 Heb LAE RE rds 1 7 14 RELAY BOARD 12 00371 01 IY DA LEVE RO be TY DRE NT CUR 1 8 5 LLOGIC BOARD i e E Ad 1 9 16 CONTROL PANEL Driver Controller 1 9 17 CONTROL PANEL Full Function Controller 1 10 18 REFRIGERATION SYSTEM COMPONENT SPEC
13. 5 Pac HIH avoa 21901 3 0 a Figure 5 12 Wiring Schematic Control Circuit 68RM35 604 42 T 302 5 13 12 09 15 FAIL DRIVER CONTROL MODULE cH 2 1 1 1 6 e4NDC 1 7 30 98 62057 Figure 5 13 Wiring Schematic Power Circuit 688 35 604 42 T 302 5 14 12 09 NOILVSNOIINOD 3 21901 5 Pac H9IH Figure 5 14 Wiring Schematic Control Circuit 68RM35 604 43 T 302 5 15 12 09 1 FAIL DRIVER CONTROL MODULE 9 1 24VDC 1 87 30 98 62080 Figure 5 15 Wiring Schematic Power Circuit 688 35 604 43 T 302 5 16 12 09 1371415 011980913 12 N3dWnr 08904 21907 08904 AVT3N 9908 21901 Figure 5 16 Wiring Schematic 68RM35 604 44 53 64 65 73 81 94 T 302 5 17 12 09 FE AVIZ 3 3908 21901 98 62086 Figure 5 17 Wiring Schematic Control Circuit 68RM35 604 45 12 09 5 18 T 302 154 60 51 a 150 1 1 2000 PTBL 30 98 62086 Figure 5 18 Wiring Schematic Power Circuit 68RM35 604 45 12 09 5 19 T 302 viva CJK wa
14. RO et SIM e fo A pae 98 62176 Figure 5 4 Wiring Schematic Control Circuit 68RM35 104 41 T 302 5 5 12 09 1504 67 70 24 V ALTERNATOR CURBSIDE 2 CR2 60 2 Isot 1 52 TI MANUAL RESET CIRCUIT BREAKER ROADSIDE CB3 60A 1 15 01 MANUAL RESET CIRCUIT BREAKER CB5 60 Isot T MANUAL RESET CIRCUIT BREAKER iso O TI MANUAL RESET CIRCUIT BREAKER PTB1 CB7 156 8 24VDC 1 CB13 150 85 FBR B lt FLOOR BLOWER e RELAY LOCKOUT ex ACSL Fa J A C FAIL SIGNAL lt BOOST PUMP 5 GRD SIGNAL 98 62176 Figure 5 5 Wiring Schematic Power Circuit 68RM35 104 41 T 302 5 6 12 09 62290 98 1 21144 22 803 11 1144 VPET N03 NOLLVSNOIINOS 3N3dWnr TavOd 21907 NOILVSNOIINOD VOS 21907 E 9 B Lt or L 2 L Le avoa N03 UNDO NIVA 6452 3514 4 35070 5 9 3040 N3d0 avoa 21901 O AN 3
15. ORE 2 3 2 3 4 BoostP ump Optional eerte e daha eme oper e cem Ud Rer ARA Ce OR 2 3 2 35 Vent MOde Rb rd e A E d 2 3 2 3 6 Compressor Unloader 2 3 2 3 7 Evaporator Fan Speed Selection 2 4 2 3 8 Fan Motor Operation Sequence 2 4 2 3 9 Condenser Fan Control sei DER aa aa E at e dead Ree d aia 2 5 2 3 10 Compressor Clutch Control 2 5 12 09 T 302 TABLE OF CONTENTS Continued PARAGRAPH NUMBER Page 2 3 11 Liquid Line Solenoid Control 2 5 2 3 12 Alarm DeSChPUON teeta bed toda whe bad ere bd 2 5 2 3 b33Ho ur Meters ih or etd dente aa ae 2 5 24 MICROPROCESSOR DIAGNOSTICS 2 5 234 15 CONTON Sine dead aa aa 2 5 2 4 2 Diagnostic pe pde ect Us pes no d Eta 2 5 2 4 3 System Parameters ca 2 6 ZAA T st ex amus 2 6 TROUBLESHOOTING
16. 68RM35 604 59 R 134A YES Wound F ield ound Field Cleanable 68R M35 604 60 R 134A YES Wound Field Wound Field Cleanable 68RM35 604 61 R 134A YES Permanent Magnet Permanent Magnet Cleanable 68RM35 604 62 R 134A YES P a Permanent Magnet Cleanable 68RM35 604 63 R 134A YES Brushless Cleanable 68 35 604 64 R 134A YES Cleanable Permanent Magnet Customer 68RM35 604 65 R 134A YES w R esistor Permanent Magnet Supplied G6RM35 604 66 R 134A VES Cleanable 68RM35 604 67 R 134A YES Wound Field WoundField Cleanable T 302 1 2 12 09 Table 1 1 Model Number Chart Continued MODEL REFRIGERANT CONTROL CONDENSER EVAPORATOR FILTER NUMBER HEAT EXCHANGER MOTOR MOTOR Cleanable R 134A YES Cleanable Cleanable R 68RM35 604 71 R 134A YES Wound Field WoundField Cleanable 68RM35 604 72 R 134A YES Wound Field WoundField Cleanable 68RM35 604 73 R 134A YES Permanent Magnet Permanent Magnet Disposable 688 35 604 74 R 134A YES Cleanable 68RM35 604 75 R 134A YES Wound Field Wound Field Cleanable 68RM35 604 76 R 134A YES Wound Field Wound Field Cleanable 68RM35 604 77 R 134A YES Permanent Magnet Permanent Magnet Cleanable 68RM35 604 78 134 YES Permanent Magnet Permanent Magnet Cleanable GBRM35 604 79 8 1348 5 Cleanable 688 35 604 80 R 134A YES Cleanable Permanent Magnet Customer 68RM35 604 81 R 134A YES Reneat Pemanen Magnet
17. C1BY AC FAIL DRIVER CONTROL MODULE C3AY FLOOR BLOVER SIGNAL z 150 K19 JP3 1 24VDC 1 98 62366 Figure 5 33 Wiring Schematic Power Circuit 68RM35 604 55 68 84 T 302 5 34 12 09 195 913405 9908 21907 814 3SIN d 35070 79 4041 4 390 po 1 16 lt 4 yo s ow 06 aw 34 Wiring Schematic Control Circuit 68RM35 604 59 69 75 85 Figure 5 T 302 5 35 12 09 ALTERNATOR CURBSIDE ROADSIDE 15 FLOOR BLOWER RELAY LOCKOUT 98 62408 Figure 5 35 Wiring Schematic Power Circuit 68RM35 604 59 69 75 85 T 302 5 36 12 09 ecrrwisnt 1193091 3409 21901 AM 3 DD te AVI WIH 3 017002 4094 4 35010 OTFOOE 3SIN d N3d0 0814 asomo ico 189 lt 4 3SIN d 35010 E79 9030 9 N3dI pee 16 1 oiu 36 Wiring Schematic Control Circuit 68RM35 604 63 70 79 86 Figure 5 T 302 5 37 12 09 BOA gt ALTERNATOR EFR1 150 24VDC 1 ACSL ra J w
18. K15 Energizes unloader 2 D30 Relay K8 output active condenser fan 16 Spare high K17 Energizes reheat coolant valve K18 Energizes the fault light output 054 Unloader 1 output active 20 5 D57 Unloader 2 output active b Connectors D63 Heat output active RCV 1 Jumpers D66 Fault output active 2 Logic board connector D69 Boost pump output active Boost pump D72 Floor blower output active J P4 A C clutch liquid line solenoid valve and fault output JP5 Floor blower relay 6 Unloaders 1 6 2 7 Evaporator fan relays J P8 24 Volt power input 9 Condenser fan relays speed relay energized 051 A C clutch and liquid line solenoid output active d Fuses F1 Logic board F7 Motor contactors and speed relays F13 other control devices Figure 1 6 Relay Board 12 00371 01 T 302 1 8 12 09 15 LOGIC BOARD 10 10 10 10 10 10 10 10 10 10 10 10 10 21901 2vAH Logic board power in Diagnostics interface RS232 DB9 Micromate Display interface Blinks once per second in normal operation Manual control inputs On steady to indicate alarms detected Interlock Inputs Off In normal operation blinks out alarm WTS low pressure switch etc codes 2 digits each when alarms detected Relay board interface Configuration J umpers Sensor inputs Thermistors etc Figur
19. Transport Air Conditioning 9 D 000009 28 OPERATION AND SERVICE for 68RM35 104 604 MICROMAX Rear Mount Air Conditioning Unit T 302 Rev D TRANSICOLD OPERATION AND SERVICE MANUAL BUS AIR CONDITIONING EQUIPMENT Rearmount 68RM35 104 604 40 amp Higher SAFETY SUMMARY GENERAL SAFETY NOTICES The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this manual They are recommended precautions that must be understood and applied during operation and maintenance ofthe equipmentcovered herein The general safety notices are presented in the following three sections labeled First Aid Operating Precautions and Maintenance Precautions A listing of the specific warnings and cautions appearing elsewhere in the manual follows the general safety notices FIRST AID An injury no matter how slight should never go unattended Always obtain first aid or medical attention immediately OPERATING PRECAUTIONS Always wear safety glasses Keep hands clothing and tools clear of the evaporator and condenser fans No work should be performed on the unit until all circuit breakers and start stop switches are turned off and power supply is disconnected Always work in pairs Never work on the equipment alone In case of severe vibration or unusual noise stop the unit and investigate MAINTENANCE PRECAUTIONS Beware of unannounced starting o
20. 267 930 100 120 12 09 4 13 302 4 16 PRESSURE TRANSDUCER CHECKOUT NOTE System must be operating to check transduc ers a With the system running use the driver display and manifold gauges to check suction and or discharge pressure s simultaneously Determine with the gages whether or both pres sure readouts are correct If one is correct exchange the pressure transducer locations If the problem Use digital volt ohmmeter to measure voltage across the transducer connector corresponding to terminals amp B See Figure 4 15 The reading should be 5 0 VDC f Use a digital volt ohmmeter to measure wire continu ity between the connector positions corresponding to C and J 6 23 Suction or C and J 6 20 Discharge See Figure 1 7 or Figure 5 2 g Use a digital volt ohmmeter measure voltage across the transducer at terminals A amp C See Figure 4 15 Compare to values in Table 4 2 A reading within two percentof the values in the table would be considered moves with the transducer replace the faulty trans ducer the driver display read out disagrees with both val ues shown on the manifold gauges proceed to step d A CAUTION Use care when checking manipulating wires plugs attached to the Logic Board Damage to the board or wiring harness can occur good O Verify that the wiring to the transducer s is in good
21. Charge system Refer to paragraph 4 7 2 4 6 4 Procedure for Evacuation and Dehydrating b O 9 System One Time Evacuation Remove refrigerant using a refrigerant recovery sys tem Refer to paragraph 4 4 4 The recommended method is connecting lines 3 8 OD copper tubing or refrigerant hoses designed for vacuum service as shown in Figure 4 6 Make sure vacuum pump valve is open Start vacuum pump Slowly open valves halfway and then open vacuum gauge valve Evacuate unit until vacuum gauge indicates 500 mi crons Hg vacuum Close off pump valve and stop pump Wait five min utes to see if vacuum holds Charge system Refer to paragraph 4 7 2 47 ADDING REFRIGERANT TO SYSTEM 4 7 1 Checking Refrigerant Charge T C a b he following conditions must be met to accurately heck the refrigerant charge Coach engine operating at high idle Unit operating fully loaded six cylinder in cool mode for 15 minutes Compressor discharge head pressure to 150 PSIG R 134a or 250 PSIG R 22 It may be necessary to condenser air flow to discharge pres sure Under the above conditions the m is properly charged when the refrigerant liquid level is at 1 2 to 3 4 of the lower receiver sight glass If itis not atthe proper level add or remove EE to bring it to the proper level Refrigerant level should not appear in the upper sight glass as this would indicate an o
22. LEDS D 2 high D 6 relay D26 relay D30 high Relay K2 output active evaporator fan speed relay energized Relay K1 output active evaporator fan energized Relay K3 output active condenser fan energized Relay K8 output active condenser fan speed relay energized 051 A C clutch and liquid line solenoid D54 D57 D66 D69 D72 output active Unloader 1 output active Unloader 2 output active Fault output active Boost pump output active Floor blower output active Figure 1 5 Relay Board 12 00371 00 1 7 T 302 1 4 RELAY BOARD 12 00371 01 O O F13 15 AMP F7 15 1 15 a Relays c LEDS Energizes evaporator fans in low speed D2 Relay K2 output active evaporator fan K2 Energizes evaporator fans in high speed high not energized in low speed speed relay energized K 7 Energizes condenser fans in low speed Relay K1 output active evaporator fan K8 Energizes condenser in high speed relay not energized in low speed energized K13 Energizes the A C clutch and liquid line D26 Relay K3 output active condenser fan solenoid valve relay 14 Energizes unloader 1 energized
23. a Remove the service valve stem caps and backseat counterclockwise both valves Remove the service port caps Connect discharge side hose tightly to the service valve port c Connect the suction side hose loosely to the other service valve port d Loosen charging center hose at dummy fitting of manifold set T 302 4 2 Frontseat clockwise both manifold gauge hand valves f Turn the service valve connected to the discharge gauge port toward frontseat clockwise approxi mately 1 4 to 1 2 turn Slowly turn the manifold discharge hand valve toward backseat counterclockwise approximately one turn Tighten charging hose onto dummy fitting Slowly turn the manifold suction hand valve toward backseat counter clockwise to remove air from line Tighten suction hose at the service valve port Frontseat close both manifold hand valves Turn the service valve connected to the suction gauge port toward frontseat clockwise approxi mately 1 4 to 1 2 turn Low Pressure High Pressure Gauge Backseated Hand Valve Frontseated Hand Valve To Low Side Access Valve To High Side Access Valve 5 Red Knob Manifold Gauge Set Hose Fitting 0 5 16 Acme Refrigeration and or Evacuation Hose SAE J 2196 R 134a Hose Fitting w O ring M14 x 1 5 High Side Field Service Coupler Low Side Field Service Coupler Figure 4 3 Manifold
24. b Weekly Inspection X Perform daily inspection See above X Check condenser evaporator coils and air filters for cleanliness x X Check refrigerant hoses and compressor shaft seal for leaks Feel filter drier for excessive temperature drop across drier c Monthly Inspection and Maintenance Perform weekly inspection and maintenance See above Clean evaporator drain pans and hoses None Check wire harasses for chafing and loose terminals Replace Tighten Check fan motor bearings None Check compressor mounting bolts for tightness None Check fan motor brushes None d Yearly Inspection and Maintenance Check drain shaft seal reservoir 4 14 1 4 2 SUCTION AND DISCHARGE SERVICE VALVES before removing the service port access valve cap The suction and discharge service valves Figure 4 1 Turning the valve stem clockwise all the way forward are provided with a double seatand a gauge port which will frontseat valve to isolate the compressor line and allows servicing of the compressor and refrigerant lines open the service port access valve Turning the valve stem counterclockwise all the way To measure suction or discharge pressure midseat the out will backseat the valve to open the line to the valve by opening the valve clockwise 1 4 to 1 2 turn compressor and close off the ga uge port normal With the valve stem midway between frontseated and operation the valve is backseated to allow full flow bac
25. 1 2 Adding Full Charge iex ses e o e Me ada Aa 4 6 4 73 Adding Partial Charge tenti edor eci UNT DR EXER PUES 61 4 6 T9302 12 09 TABLE OF CONTENTS Continued PARAGRAPH NUMBER Page 48 CHECKING FOR NONCONDENSIBLES 4 6 49 AND REPLACING HIGH OR LOW PRESSURE SWITCH 4 7 4 10 FILTER DRIER 22 0 tees a edt I Eat men Rae xe Red d 4 7 410 TO Check Filter Drier a pha EUR XR 4 7 4 10 2 To Replace 4 7 4 11 SERVICING THE LIQUID LINE SOLENOID VALVE 4 8 A ALL Coil Replacement e A tear eG 4 8 4 11 2 Internal Part 4 8 4 11 3 Replace Entire Valve Bee RR Ged 4 8 412 THERMOSTATIC EXPANSION VALVE 4 8 4 12 1 Valve Replacement en ee eee pt 4 9 4 12 2 Superheat Measurement 4 9 413 REPLACING RETURN AIR FILTERS 4 10 4 14 COMPRESSOR MAINTENANCE
26. 5 12 Figure 5 12 Wiring Schematic Control Circuit 68R 35 604 42 5 13 Figure 5 13 Wiring Schematic Power Circuit 68RM35 604 42 5 14 Figure 5 14 Wiring Schematic Control Circuit 68 35 604 43 5 15 Figure 5 15 Wiring Schematic Power Circuit 68RM35 604 43 5 16 T 302 iv 12 09 FIGURE NUMBER Page Figure 5 16 Wiring Schematic 68RM35 604 44 53 64 65 73 81 94 5 17 Figure 5 17 Wiring Schematic Control Circuit 68RM35 604 45 5 18 Figure 5 18 Wiring Schematic Power Circuit 68RM35 604 45 5 19 Figure 5 19 Wiring Schematic 68RM35 604 46 5 20 Figure 5 20 Wiring Schematic Control Circuit 688RM35 604 47 5 21 Figure 5 21 Wiring Schematic Power Circuit 68RM35 604 47 5 22 Figure 5 22 Wiring Schematic Control Circuit 68RM35 604 48 5 23 Figure 5 23 Wiring Schematic Power Circuit 68RM35 604 48 5 24 Figure 5 24 Wiring Schematic Control Circuit 688 35 604 49 72 5 25 Figure 5 25 Wiring Schematic Power Circuit 68RM35 604 49 72 5 26 Figur
27. 83 5 41 Figure 5 41 Wiring Schematic Control Circuit 688RM35 604 71 87 5 42 Figure 5 42 Wiring Schematic Power Circuit 68RM35 604 71 87 5 43 Figure 5 43 Wiring Schematic Control Circuit 688RM35 604 90 92 5 44 Figure 5 44 Wiring Schematic Power Circuit 68RM35 604 90 92 5 45 Figure 5 45 Wiring Schematic Control Circuit 68RM35 604 91 94 5 46 Figure 5 46 Wiring Schematic Power Circuit 68RM35 604 91 94 5 47 Figure 5 47 Wiring Schematic Control Circuit 688RM35 604 95 5 48 Figure 5 48 Wiring Schematic Power Circuit 68RM35 604 95 5 49 Figure 5 49 Wiring Schematic Control Circuit 688RM35 604 96 5 50 Figure 5 50 Wiring Schematic Power Circuit 68RM35 604 96 5 51 12 09 V T 302 LIST OF ILLUSTRATIONS Continued LIST OF TABLES TABLE NUMBER Page Table 1 1 Model Number Chart 4 2 2 2 2 4 2 2 1 2 Table 1 1 Model Number Chart Continued 1 3 Table 1 2 Additional Support Manuals 1 3
28. 9 4 psig 3 67 0 27 bar High Pressure Switch HPS R 22 Units Opens at 425 10 psig 29 29 0 68bar Closes at 300 10 psig 20 41 0 68bar R 134a Units Opens at 300 10 psig 20 41 Closes at 200 10 psig 13 61 R 134a High Ambient Units Opens at 350 10 psig 23 81 Closes at 240 10 psig 16 31 Low Pressure Switch LPS Opens at 6 3psig 0 41 0 20 bar Closes at 25 3 psig 1 7 0 20 bar Water Temperature Switch WTS Bus manufacturer supplied suggested close on temperature rise at 105 F 41 C 0 68bar 0 68bar 0 68bar 0 68bar 12 09 19 ELECTRICAL SPECIFICATIONS CONDENSER MOTORS MOTOR TYPE WOUND FIELD PERMANENT MAGNET BRUSHLESS refer to Table 1 1 Voltage 27 27 27 VDC 24 28 VDC Horsepower kW NEM 8 0 5 0 6 0 37 0 75 0 56 0 5 0 37 Full Load Amps 3202 Operating Speed High Low RPM Bearing Lubrication or permanent magnet with resistor applications Resistor 420 watts 1800 1400 1800 1800 Factory Lubricated Factory Lubricated Factory Lubricated additional grease not additional grease not additional grease not required required required 1 10 ELECTRICAL SPECIFICATIONS SENSORS AND TRANSDUCERS Suction and Discharge Pressure Transducer Supply Voltage 4 5 to 5 5 5 nominal Input Range 6 7 to 450 psig 0 46 to 30 62 bar Output Voltage 0 0098 x psig 0 4659 See Table 4 2 for calculatio
29. CONDENSER FAN MOTOR OVERLOAD CONDENSER SPEED RELAY DISCHARGE PRESSURE TRANSDUCER EVAPORATOR FAN RELAY EVAPORATOR FAN MOTOR EVAPORATOR FAN MOTOR OVERLOAD EVAPORATOR SPEED RELAY FUSE HIGH PRESSURE SWITCH EVAPORATOR 1 2 RELAY EVAPORATOR HIGH SPEED RELAY CF1 2 RELAY CONDENSER HIGH SPEED RELAY CLUTCH RELAY UV1 RELAY UV2 RELAY FRESH AIR RELAY HEAT RELAY FAULT RELAY BOOST PUMP RELAY FLOOR BLOWER RELAY EVAPORATOR FAN HIGH RELAY EVAPORATOR FAN LOW RELAY CONDENSER FAN HIGH RELAY CONDENSER FAN LOW RELAY LOW PRESSURE SWITCH LIQUID LINE SOLENOID VALVE POWER RELAY RESISTOR 1500 OHMS SW OEM SUPLIED RETURN AIR SENSOR REHEAT COOLENT VALVE HEAT VALVE SUCTION PRESSURE TRANSDUCER UNLOADER SOLENOID VALVE WATER TEMPERATURE SWITCH CONNECTOR LEGEND DESCRIPTION LOGIC POWER CONNECTOR DISPLAY INTERFACE ON TEST CONNECTOR INPUT CONNECTOR RELAY BOARD INTERFACE CONNECTOR SENSOR CONNECTOR DIAGNOSTIC INTERFACE MOTOR OVERLOAD CONNECTOR LOGIC BOARD INTERFACE CONNECTOR BOOST PUMP CONNECTOR CLUTCH FAIL CONNECTOR HEAT CONNECTOR UNLOADER VALVE CONNECTOR EVAPORATOR FAN SPEED CONNECTOR 24 VOLT POWER CONDENSER FAN SPEED CONNECTOR Figure 5 1 Wiring Schematic Legend T 302 5 2 12 09 62125 98 2814 quo F T p 2 ADT NOILVSNOIINOD N3dWnr 21901 5 2 AVT3H HJIH 3 ONDI l
30. Fan Motor Removal 4 18 REMOVING THE CONDENSER FAN MOTOR When removing or installing the condenser fan motor care should be exercised to prevent any damage to the condenser coil a b Place the main battery disconnect switch in the OFF position and lock Disconnect the wire leads to the motor Mark the leads for proper reassembly Remove fan blade Loosen the two retaining screws in the fan blade hub The fan blade should remain on the shaft of the motor but free to slide on the shaft of the motor Remove the four motor mounting bolts securing the motor motor mount the unit referto Figure 4 16 Remove the motor by sliding the motor down and out from the fan blade and unit The fan blade should remain in the cavity between the condenser coil and fan shroud until the motor is free of the unit When installing the motor use an adhesive to secure the shaft key to the motor shaft or fan hub slot and apply an anti seize compound to the motor shaft Place the motor motor mount back into position but leave the motor mounting bolts loose until the fan blade has been reinstalled on the motor shaft 12 09 Tighten the four motor mounting bolts refer to Figure 4 16 Position the fan blade 1 3 the height of blade below the shroud tighten the two retaining screws in the fan hub 4 19 SERVICING THE EVAPORATOR FAN BLOWER MOTOR ASSEMBLY 4 19 1 Removing and Disassembling Place main battery discon
31. Gauge Set R 134a 4 3 1 Installing R 134a Manifold Guage Set A R 134a manifold gauge hose set with self sealing hoses is required for service of models covered within this manual The manifold gauge hose set is available from Carrier Transicold Carrier Transicold P N 07 00294 00 which includes items 1 through 6 Figure 4 3 To perform service using the manifold gage hose set do the following a Preparing Manifold Gauge Hose Set For Use 1 If the manifold gauge hose set is new or was exposed to the atmosphere it will need to be eva cuated to remove contaminants and air as follows 12 09 2 Back seat turn counterclockwise both field service COD SIS see Figure 4 3 and midseat both hand valves Connect the yellow hose to a vacuum pump and an R 134a cylinder Evacuate to 10 inches of vacuum and then charge with R 134a to a slightly positive pressure of 1 0 psig Frontseatboth manifold gauge sethand valves and disconnect from cylinder The gauge set is now ready for use b Connecting Manifold Gauge Hose Set To connect the manifold gauge hose set for reading pressures do the following 1 Remove service valve stem cap and check to make sure itis backseated Remove access valve cap 2 Connectthe field service coupler see Figure 4 3 to the access valve Turnthe field service coupling knob clockwise which will open the system to the gauge set 4 Read system pressures 5 Repeat the procedure to co
32. Return air tempera ture sensor failure or wiring defective Suction pressure transducer failure or wiring defective Discharge pressure transducer failure or wiring defective Low suction pressure switch open or wiring defective 3 2 Check causes of coil freezing Refer to section 3 3 6 Check repair or re place wiring or alter nator Ensure all connectors are plugged in Check sensor resistance or wiring Refer to para graph 4 15 Replace sensor or repair wir ing Ensure all connectors are plugged in Check sensor voltage or wir ing Replace sensor or repair wiring Ensure all connectors are plugged in Check sensor voltage or wir ing Replace sensor or repair wiring Check cause of low suction pressure Re fer to section 3 3 3 An alarm will be gener ated and the system will shutdown The evapora tor fans will remain run ning while the compres sor is off The system is shut down until the voltage returns to normal levels The system is shut down until the voltage returns to normal levels All outputs except the evaporator fans will be de energized Both unloaders are ener gized One unloader is energi zed Condenser fans will run on high speed The clutch is de ener gized for the minimum off time The evaporator fans will remain running during this period After the compressor cycles off three times in 30 min utes all outputs will be de energized exc
33. S se 3SIN d 35070 79 1 4 N3dD 19 to 1 98 03280 47 Wiring Schematic Control Circuit 68RM35 604 95 Figure 5 12 09 5 48 T 302 PTB1 154 gt A C FAIL DRIVER CONTROL MODULE 150 K19 2 1 24VDC 97 98 03280 Figure 5 48 Wiring Schematic Power Circuit 688 35 604 95 12 09 5 49 T 302 NOILVSNOIANOD 3908 21901 ANSIO 98 03295 49 Wiring Schematic Control Circuit 68RM35 604 96 Figure 5 12 09 5 50 T 302 o ALTERNATOR I A C FAIL DRIVER CONTROL MODULE S FLOOR HEAT ACTIVATE SIGNAL M lt BLOWER LOW SPEED SIGNAL BOOST PUMP 98 03295 Figure 5 50 Wiring Schematic Power Circuit 68RM35 604 96 12 09 5 51 T 302 A Air Filter 4 10 Alarm 2 5 3 1 Alarm Clear 3 1 Alarm Codes 3 1 Alarm Queue 3 1 Ambient Lockout 1 11 Boost Pump 2 3 C Circuit Breaker 1 11 Clutch 2 5 4 11 Compressor 1 4 1 10 4 10 Condenser Fan 2 5 Condenser Fan Motor 4 14 Condensing Section 1 1 Control Panel 1 9 1 10 Cooling Mode 2 3 D DESCRIPTION 1 1 Diagnostics 2 1 2 5 Discharge Pressure 2 3 Evacuation 4 5 One Time 4 6 Evacuation Triple 4 5 Evaporator 1 4 Evaporator Fan 2 4 12 09 INDEX F Fa
34. and re open system f Connect wire leads and test operation 6 Eby 7 22 8 1 Snap Gasket 2 Coil Assembly Piston Assembly 3 Enclosing Tube Body Assembly Bracket Adapter 4 Plunger Assembly Figure 4 9 Liquid Line Solenoid Valve 4 12 THERMOSTATIC EXPANSION VALVE The thermostatic expansion valve Figure 4 10 is an automatic device which maintains constant superheat of the refrigerant gas leaving the evaporator regardless of suction pressure The valve functions are a automatic control of refrigerant flow to match the evaporator load and b prevention of liquid refrigerant entering the compressor Unless the valve is defective it seldom requires any maintenance 12 09 4 Gasket 5 Cage Assembly 1 Power Head Assembly 2 Equalizer Connection 6 Body Flange 3 Bulb 7 Cap screw Figure 4 10 Thermostatic Expansion Valve 4 12 1 Valve Replacement a b 241 down low side of the unit Refer to paragraph Remove insulation from expansion valve bulb See Figure 4 10 and Figure 4 11 Loosen retaining straps holding bulb to suction line and detach bulb from the suction line Loosen flare nuts on equalizer line and disconnect equalizer line from the expansion valve Remove capscrews and lift off power head and cage assemblies and gaskets Check clean and remove any foreign material from the valve body valve seat and mating surfaces If
35. be checked for cleanliness periodically depending on operating conditions A dirty filter will restrict air flow over the evaporator coil which may cause insufficient cooling or heating and possible frost buildup on the coil To remove the filters do the following a Place main battery disconnect switch in OF F position and lock b Remove the return air grille c Loosen filter retaining hardware and remove the filter from the grille d Reverse procedure to install new filters 4 14 COMPRESSOR MAINTENANCE 4 14 1 Shaft Seal Reservoir If compressor is fitted with a shaft seal reservoir it is recommended that the reservoir is serviced checked and drained atleast once a year Refer to the 05G Twin Port workshop manual 62 11052 for complete instructions 4 14 2 Removing the Compressor If compressor is inoperative and the unit still has refrigerant pressure isolate the compressor and remove the refrigerant Refer to paragraph 4 4 2 If compressor is operative perform a pump down Refer to paragraph 4 4 3 a Place main battery disconnect switch in OFF position and lock b Tag and disconnect wiring to the high pressure and low pressure switch unloaders and clutch Remove tension on drive belts remove drive belts d Loosen bolts at suction and discharge service valve flanges and break seal to be sure pressure is re leased Remove bolts e Remove four bolts holding compressor to base f Attach sling or oth
36. closes a set of contacts to energize the condenser fan HIGH SPEED relay K8 Relay K8 closes its contacts to energize the condenser speed relay CSR With the CSR contacts closed power flows directly to ground from the permanent magnet motors or through the motor High speed speed circuit A2 to 53 for wound field motors When evaporator fan operation is required the microprocessor energizes grounds relay K22 which closes a set of contacts to energize the evaporator fan ON relay K1 Relay K1 closes it s contacts to energize evaporator fan relays EFR1 amp EFR2 With permanent magnet motors a circuit is established from circuit breaker CB3 to the motors in series placing them in low speed For wound field motors the circuit is established through the motor low speed circuits A2 to 52 T 302 2 4 When high speed evaporator fan operation is required the microprocessor energizes grounds relay K21 which closes a set of contacts to energize the evaporator fan HIGH SPEED relay K2 Relay K2 closes its contacts to energize the evaporator speed relay ESR With permanent magnet motors the ESR contacts reverse from CB2 directly to EM2 and power from directly to placing them in high speed For wound field motors the circuit ee through the motor high speed circuit A2 to 53 2 3 8 2 Relay Board 12 00371 01 On systems with relay board 12 00371 01 see Figure 1 6 Power is available from relay board ter
37. condition Figure 4 15 Transducer Terminal Location Table 4 2 Pressure Transducer Voltage Voltage Psig Voltage Psig Voltage Psig Voltage Psig Voltage Psig Voltage 2 0558 1397 150 1536 205 2475 260 3014 Voltage 50 0555 105 1495 160 2034 215 2573 0465 5s 107 mo 154 165 2083 220 262 25 3161 5 oss eo 155 15 1593 17 212 225 2671 280 3210 125 0712 1250 185 1789 190 2328 245 2867 300 2406 3 osi 90 1346 1587 200 2426 255 2965 3504 4 17 REPLACING SENSORS AND TRANSDUCERS a Place main battery disconnect switch in OFF position and lock b Tag and disconnect wiring from defective sensor or transducer Remove and replace defective sensor or transducer Sensor transducer connections are fitted with Schreader valves to facilitate replacement T 302 d Connect wiring to replacement sensor or transducer e Checkout replacement sensor or transducer Refer to section 4 15 or 4 16 as applicable f Repair or replace any defective component s as re quired 12 09 Position 1 3 of blade height below shroud 5 Fan Blade 6 Shroud 7 Fan Blade Guard 1 Condenser Coil 2 Fan Blade Hub 3 Retaining Set Screw 4 5 16 Ratchet Wrench Figure 4 16 Condenser
38. length replace them a b Remove brush covers With fingers or suitable hook lift the brush spring end up so the brush may slide up and out of the holder Loosen the brush screw to remove the brush shunt terminal Remove brush T302 To replace lift brush spring and place brush in holder Position spring end on top of the brush d Connect the brush shunt terminal to its proper crossover with the brush screw assembled loosely L nm rci Haa dor ror p p rra REMOVAL DISASSEMBLY 1 1 16 ASSEMBLY 1 Blower Housing 2 Fan Blower 3 Venturi Ring 4 Venturi Retaining Clip 5 Clip Mounting Bolt 6 Evaporator Motor 7 Mounting Bolt 8 Wire J unction Box 9 Hub Set Screw Figure 4 17 Evaporator Fan Blower Removal T 302 4 16 e Assure positioning of brush to permit the brush shunt to travel freely in the holder slot as the brush wears If it hangs up commutator damage and motor failure will result f Tighten screw 4 20 SERVICING THE REHEAT COOLANT VALVE The reheat coolant valve RCV requires no maintenance unless a malfunction of the internal parts or coil damage occurs This may be caused by foreign mater
39. omission of the coil housing or plunger 4 Mechanical interface with movement of plunger which may be caused by a deformed enclosing tube Failure to open may be caused by the following 1 Coil burned out or an open circuit to coil connections 2 Improper voltage 3 Defective plunger or deformed valve body assembly Failure to close may be caused by the following 1 Defective plunger or deformed valve body assembly 2 Foreign material in the valve 4 11 1 Coil Replacement It is not necessary to remove the refrigerant charge from the system b Place main battery disconnect switch in OFF position and lock Disconnect wire leads to coil Remove coil retaining clip and nameplate Lift burned out coil from enclosing tube and replace Connect wire leads and test operation 11 2 Internal Part Replacement low side pump down Refer to paragraph pro b Carefully loosen enclosing tube assembly and ensure no pressure remains within the valve Disassemble valve and replace defective parts c Assemble valve and leak check d Evacuate low side and re open system T 302 4 11 3 Replace Entire Valve a Perform a low side pump down refer to paragraph 4 4 1 Remove coil and plunger assembly and un braze valve from lines Remove valve assembly from bracket c Disassemble new valve to protect internal parts and solder to lines d Assemble and leak check valve e Evacuate low side
40. re quired replace valve body NOTE R 134a valves are non adjustable Using new gaskets install new cage and power head assemblies Fasten equalizer line to the expansion valve Leak check the new valve and evacuate and dehy drate low side Refer to paragraph 4 6 The thermal bulb is installed below the center of the suction line four or eight o clock position This area must be clean to ensure positive bulb contact Strap thermal bulb to suction line Ensure that retaining straps are tight and renew insulation If required add vapor refrigerant to bring low side pressure to 20 to 30 PSIG R 134a or 45 to 60 PSIG R 22 Open filter drier inlet service valve and com pressor service valves Run the coach for approximately 30 minutes on fast idle 12 09 m Check refrigerant level Refer to paragraph 4 7 1 n Check superheat Refer to paragraph 4 12 2 4 12 2 Superheat Measurement O All readings must be taken from the TXV bulb location and out of the direct air stream 1 Suction Line section view 2 TXV Bulb Clamp 3 Nut amp Bolt clamp 4 Thermocouple 5 TXV Bulb Shown in the 4 clock position Figure 4 11 Thermostatic Expansion Valve Bulb and Thermocouple Remove Presstite insulation from expansion valve bulb and suction line Loosen TXV bulb clamp and make sure area un der clamp is clean Place t
41. system to stabilize for ten to fifteen minutes and check for the following a Listen for abnormal noises in compressor or fan mo tors b Check compressor oil level Refer to section 4 14 4 c Check refrigerant charge Refer to section 4 7 1 d Ensure that self test has been successfully per formed and that there are no errors or alarms indi cated Refer to section 2 1 3 COOL HIGH SPEED LOADED COOL HIGH SPEED 4CYLINDERS COOL LOW SPEED 2 CYLINDERS SETPOINT REHEAT DUTY CYCLE 0 100 LOW SPEED 4CYLINDERS HEAT LOW SPEED HEAT HIGH SPEED Cool 2 3 MODES OF OPERATION The system is operated by a Carrier Transicold Micromax microprocessor controller which consists of a logic board Figure 1 7 relay board Figure 1 5 and manual operator switches The logic board regulates operational cycles of the system by energizing or de energizing Relay Board relays in response to deviations in interior temperature Modes of operation include Cooling Heat and Vent Referto Figure 2 1 and the following paragraphs fora description of each mode Figure 2 1 shows the Logic Board actions at various temperature deviations from setpoint On rising temperature changes occur when the temperature rises above Logic Board setpoints On falling temperature changes occur when temperatures falls below Logic Board set point The system will operate in these modes unless pressures override the Logic Board settings SETP
42. to coil c Remove coil retaining screw and nameplate d Lift bumed out coil from enclosing coil assembly and replace e Connect wire leads and test operation 12 09 4 20 3 Replacing the Internal Valve Parts a b WARNING Be careful of remaining hot coolant in the hoses when disassembling Drain the heater coil Disassemble valve and replace defective parts Assemble valve and connect coolant hoses 4 20 4 Replacing the Valve Assembly a b C Drain the heater coil Disconnect wire leads to the solenoid coil Disconnect the hoses from both sides of the valve assembly Remove the hex nutand washer securing the valve assembly to the valve bracket Remove the valve bracket assembly from the panel Remove valve assembly from the unit Install new valve and re connect hoses It is not necessary to disassemble the valve when installing Fill the system with coolant Connect wire leads and test operation T302 4 21 LOGIC BOARD REPLACEMENT Control configuration is preset at factory and resetting of the parameters is not advised If a replacement Logic Board is installed itis necessary to match the configuration jumpers See Figure 1 7 to the original board Table 4 3 coe a list of jumper functions Carrier is not responsible for failures or damage resulting from unauthorized changes Table 4 3 Logic Board Configuration Configuration High Reheat When this configura
43. will remain energized until the pressure increases to above 34 psig R 134a or 56 psig R 22 2 Compressor Unloader UV2 Relay When suction pressure decreases below 23 psig R 134a or 46 psig R 22 unloader UV2 is energized unloading the second compressor cylinder bank this output will remain energized until the pressure increases to above 31 psig R 134a or 52 psig R 22 c Discharge Pressure Discharge pressure is also controlled by the unloaders 1 Compressor Unloader UV1 Relay When the dis charge pressure increases above set point A see chart below unloader UV1 is energized this un loader will remain energized until the pressure de creases below set point B see chart below Table 2 1 Unloader UV1 Relay Set PointA Set Point B PSIG PSIG Lm pm igh Ambien 425 R 22 T 302 2 Compressor Unloader UV2 Relay On R 134a sys tems when the discharge pressure increases above set point A see chart below unloader UV2 is ener gized this unloader will remain energized until the ressure decreases below set point see chart be ow On R 22 systems this unloader is not con trolled by discharge pressure Table 2 2 Unloader UV2 Relay Set PointA Set Point B PSIG PSIG m opm A 2 3 7 Evaporator Fan Speed Selection Temperature control is the primary method of determining the fan speed selection Section 2 3 8 1 or section 2 3 8 2 describe re
44. with exposed skin oreyes Using two open end wrenches slowly crack open the flare nuts on each side of the filter drier Remove the filter drier f Remove seal caps from the new filter drier Apply a light coat of compressor oil to the flares Assemble the new filter drier to lines ensuring that the arrow on the body of the filter drier points in the direction of the refrigerant flow refrigerant flows from the receiver to the evaporator Finger tighten flare nuts Tighten filter drier flare nuts using two open end wrenches i Evacuate the filter drier and lines by connecting a vacuum pump as shown in Figure 4 4 Evacuate to 500 microns Backseat fully close both service valve ports and re place valve caps Test filter drier for leaks Check refrigerant level T302 4 11 SERVICING THE LIQUID LINE SOLENOID VALVE The Liquid line solenoid valve Figure 4 9 is very similar to the reheat coolant valve It requires no maintenance unless a malfunction to the internal parts or coil occurs This may be caused by foreign material such as dirt scale or sludge in the refrigeration system or improper voltage to the coil There are only three possible valve malfunctions coil burnout failure to open or failure to close Coil burnout may be caused by the following 1 Improper voltage 2 Continuous over voltage more than 10 or under voltage of more than 15 3 Incomplete magnet circuit due to the
45. 29 T 302 Figure 5 28 Wiring Schematic Control Circuit 68RM35 604 52 80 12 09 AC POWER SWITCH HIN NOT TO BATTERY SOURCE CB7 15 19 1 1 lt 0 0 24VDC 30 24V RELAY _ MULTIPLEX BOOST PUMP SIGNAL 98 62334 Figure 5 29 Wiring Schematic Power Circuit 68RM35 604 52 80 T 302 5 30 12 09 awasi NOILVYNOIINOD N3dWnr 08908 31907 3 mE C5 quvgg AVI2 N04 ANNOY 35010 4080 4 N3dO n O 0002 4080 4 35010 AN 3 OL FOO 358 4 N3dO 1 O HOIH N 3 WAJ qavod AV 138 30 Wiring Schematic Control Circuit 68RM35 604 54 62 78 Figure 5 T 302 5 31 12 09 C8 gt 24 V ALTERNATOR 15 24VDC 18 A C FAIL DRIVER CONTROL MODULE 9 166 Y A D67 e 1 24VDC PTB1 30 87 98 62340 Figure 5 31 Wiring Schematic Power Circuit 688 35 604 54 62 78 T 302 5 32 12 09 arvasi fenar NDILV N9IANDO davOd 21907 Figure 5 32 Wiring Schematic Control Circuit 68RM35 604 55 68 84 T 302 5 33 12 09 BOA PO 2h V BATTERY
46. EFRI CFR2 19 18 17 16 15 14 3 4 5 6 22 H ERIT a ces NU 13 18 17 16 15 14 20 21 7 19 7 C D qos gt 52888 2 EFRI CERT ESR R 13 17 15 12 14 20 21 19 1 Relay Board 13 Power Terminal Block 2 Logic Board 14 Condenser Speed Relay 3 5 Condenser Motor 41 15 Condenser Fan 1 Relay 4 4 Condenser Motor 2 16 Condenser Fan 2 Relay 5 Evaporator Motor 1 17 Evaporator Fan 1 Relay 6 2 Evaporator Motor 2 18 Evaporator Fan 2 R
47. IFICATIONS 1 10 19 ELECTRICAL SPECIFICATIONS CONDENSER MOTORS 1 11 110 ELECTRICAL SPECIFICATIONS SENSORS AND TRANSDUCERS 1 11 111 ELECTRICAL SPECIFICATIONS EVAPORATOR MOTORS 1 11 1 32 SAFETY DEVICES nn dead ente e Re DEA E eet aa dead eene eaa ed eet 1 11 1 13 AIR CONDITIONING REFRIGERATION CYCLE 1 12 1 14 HEATING CY CEE ah eR RE po ca e RR RIA de ERE E A Pa 1 12 OPERATION d e nC CR sos OE Moos S Ca RR GUN 2 1 21 STARTING STOPPING AND OPERATING INSTRUCTIONS 2 1 231 Logic iisi dasa 2 1 2 1 2 Starting E atte teh Pd each N 2 1 2 1 3 Self Test and Diagnostics Check for Errors and or 5 2 1 214 Stopping ek eer ee Rb ra s dc Rara pa 2 2 2 2 PRE TRIP INSPECGTION 3 3 cu drat Curr tei d e UE uta 2 2 2 3 MODES OF OP ERAT ION e a E a e s 2 2 2 3 1 Temperature 52556 er RARI he RU ARE se ce RE 2 3 2 3 2 6001 0 Aan Aaa URBES 2 3 2 3 3 Heating Mode se a ER Uia Gee ER
48. J 3 when testing is com pleted or the system will fail to operate when the Micromate is disconnected NOTE When modifying the setpoint temperature for diagnostic purposes be sure to reset the set point when testing is complete 2 4 2 Diagnostic Mode The diagnostic mode can be entered by pressing the UP and DOWN arrow keys simultaneously for 3 seconds The Micromate display screen will go blank for one second and then enter the alarm screen The diagnostic mode allows alarms and system parameters to be viewed If there are any alarms stored the most recent alarm will be shown To exit the diagnostic mode press the ON OFF key once or do not touch any keys for 30 seconds To view additional alarm information refer to section 3 T 302 2 4 3 System Parameters To view system parameters first enter the Diagnostic Mode Refer to paragraph 2 4 2 The parameters are shown in Table 2 4 While in the diagnostic mode press an UP orDOWN arrow key to switch the display to the Parameter Display With the first Parameter displayed press the DOWN arrow key to scroll through the list from the first to the last parameter or press the UP arrow to scroll from the last to the first parameter When scrolling through the parameters the current parameter will be displayed for two seconds After two seconds the display will show the data for the current parameter When the last parameter is reached the list will wrap back to 1 2 4 4 Test M
49. Maintenance Alarm 2 The evaporator hour Reset the mainte Alarm will be generated meter is greater than nance hour meter the value in Mainte nance Hour Meter 2 Low Pressure Warning Suction pressure low Check cause of low Alarm will be generated enough to energize suction pressure Re fer to section 3 3 3 High Pressure Warning Discharge pressure Check cause of high Alarm will be generated high enough to discharge pressure energize UV2 to section Alarm Queue Full All locations of the Record and clear Alarm will be generated alarm queue are cur alarm queue rently full and no more alarms can be saved 12 09 3 3 T 302 Table 3 3 General System Troubleshooting Procedures INDICATION REFERENCE TROUBLE POSSIBLE CAUSES SECTION 3 3 1 System Will Not Cool Compressor will not run Active system alarm V Belt loose or defective Clutch coil defective Check R eplace Clutch malfunction Check R eplace Compressor malfunction See Table 1 2 Electrical malfunction Coach power source defective Check R epair Circuit Breaker safety device open Check R eset 3 3 2 System Runs But Has Insufficient Cooling Compressor V Belt loose or defective Check Compressor valves defective See Table 1 2 Refrigeration system Abnormal pressures No or restricted evaporator air flow Expansion valve malfunction Restricted refrigerant flow Low refrigerant charge Service valves partially closed S afety device open Liquid solenoid valve
50. OINT HEAT HIGH SPEED Heat Figure 2 1 Capacity Control Diagram T 302 12 09 2 3 1 Temperature Control Temperature is controlled by maintaining the return air temperature measured at the return air grille 2 3 2 Cooling Mode Cooling is accomplished by energizing the compressor and condenser fans opening the liquid line solenoid valve and closing the heating valve Once interior temperature reaches the desired set point the system may operate in the clutch cycle or reheat mode Selection of clutch cycle or reheat is factory programmed in accordance with the bus purchase specification A controller programmed for clutch cycle will de energize the compressor clutch and allow the system to operate in the vent mode until further cooling is required A controller programmed for reheat will maintain compressor operation and cycle the heat valve to allow reheating of the return air In the reheat mode interior temperature is maintained at the desired set point while additional dehumidification takes place 2 3 3 Heating Mode In the heat mode the liquid line solenoid is closed and the compressor and condenser fans are shutdown The heat valve is opened to allow a flow of engine coolant through the heat section of the evaporator coil The evaporator fans speed is varied as required to circulate air over the evaporator coil based on the temperature difference from setpoint Operation in the heating mode is controlled by the
51. R indi cator is illuminated If the controller cycles back to the INSIDE AIR indicator then the controller is pro grammed to display return air temperature If the controller does not automatically cycle back to the return air indicator then the controller is grammed to display set point temperature 6 startthe system press the 1 0 button to illuminate the indicator light and signal the Logic Board to per form start up Ensure the AUTO button indicator is illuminated If not press the AUTO button to place the system in the automatic mode After the pre trip inspection is completed the switches may be in accordance with the desired control modes 7 If cooling only heating only or ventilation only is de sired press the corresponding button refer to Figure 1 9 to illuminate the indicator light and place the system in that mode of operation 8 Iflow or high speed evaporator fan speed is desired press the FAN SPEED button to illuminate the indi cator light and bring speed to the desired level 9 To open or close the fresh air damper if supplied press the FRESH AIR button to illuminate the indica tor light and bring the damperto the desired position 10 To read interior or exterior temperature press the TEMPERATURE button to illuminate the indicator light and bring the display to the desired temperature After a short delay the display will return to the default set point or return air temp
52. Schematic Power Circuit 68RM35 604 48 T 302 5 24 12 09 carr NOILVSNOIJNOD N3idWnr avoa 21907 017002 094 35070 OTFOOE 3515 9 340 avoa 31907 3SIN d 35070 ET9 390 Figure 5 24 Wiring Schematic Control Circuit 68RM35 604 49 72 T 302 5 25 12 09 CURBSIDE ROADSIDE PTD FLOOR BLOWER HIGH SPEED SIGNAL 3 lt r K K18 P4 I lt A C FAIL DRIVER CONTROL MODULE 5 FLOOR HEAT ACTIVATE SIGNAL T rum BLOVER LOV SPEED SIGNAL 158 24 0 1 98 62396 Figure 5 25 Wiring Schematic Power Circuit 68RM35 604 49 72 T 302 5 26 12 09 NOILVNOSIJNDO W3dWnr 21907 19 C o van 26 Wiring Schematic Control Circuit 68RM35 604 50 51 58 74 Figure 5 T 302 5 27 12 09 1504 24 404 JPS 5 BOOST PUMP SIGNAL BPS 98 62295 74 Figure 5 27 Wiring Schematic Power Circuit 68RM35 604 50 51 58 T 302 5 28 12 09 9r or 1 O HIH 3 avoa 31907 017002 4 30 4 35072 OTFOOE 3SIN d 390 er E ET E E E E s n H EI L i s EI 0 OMNES Aree 5
53. Table 2 1 Unloader UV1 Relay 2 3 Table 2 2 Unloader UV2 Relay 2 4 Table 2 4 Parameter Codes Dee Sart hacks Park COR a a ea A 2 7 Tables Error Codes e me ato de ok i noe et e 3 1 Table 3 2 Alarm Codes DELE E tl Rete ONCE E BR cR GC 3 2 Table 3 3 General System Troubleshooting Procedures 3 4 Table 4 1 Temperature Sensor Resistance 4 12 Table 4 2 Pressure Transducer Voltage 4 13 Table 4 3 Logic Board Configuration 4 17 Table 4 4 R 22 Temperature Pressure 4 18 Table 4 5 R 134a Temperature Pressure Chart 4 19 T 302 vi 12 09 SECTION 1 DESCRIPTION 11 INTRODUCTION This manual contains Operating Instructions Service Instructions and Electrical Data for Model 68RM35 Air Conditioning and Heating equipmentlisted in Table 1 1 Model 68RM35 systems see Figure 1 1 consists of a one piece air conditioning unit assembly containing the condenser amp evaporator and engine compartment Compressor Refrig
54. The thermostatic expansion valve T 302 reduces pressure and temperature of the liquid and meters the flow of liquid refrigerant to the evaporator to maximum use of the evaporator heat transfer surface The low pressure low temperature liquid that flows into the evaporator tubes is colder than the air that is circulated over the evaporator tubes by the evaporator fans Heat transfer is established from the evaporator air flowing over the tubes to the refrigerant flowing inside the tubes The evaporator tubes have fins to increase heat transfer from the air to the refrigerant therefore the cooler air is circulated to the interior of the bus Liquid line solenoid valve closes during shutdown to prevent refrigerant flow The transfer of heat from the air to the low temperature liquid refrigerant in the evaporator causes the liquid to vaporize This low temperature low pressure vapor passes through the heat exchanger if so equipped where additional heat is transferred to ensure the refrigerant entering the compressor is in a vapor state The refrigerant then continues through the suction line and returns to the compressor where the cycle repeats 1 14 HEATING CYCLE A heating coil is furnished in the unit assembly Components furnished by the bus manufacturer may include a water temperature switch WTS and boost water pump A solenoid operated reheat coolant valve may be supplied by the bus manufacturer or by Carrier Tran
55. ant cylinder on scale Pre are to charge vapor refrigerant by connecting charg ing hose from container to center connection on gauge manifold Purge air from hoses Run the unit the cool mode as described in section 4 7 1 With the suction service valve midseated open the refrigerant cylinder valve and add vapor charge until the refrigerantlevel appears in the lower receiver sightglass Underthe above conditions the system is properly charged when the refrigerant liquid level is at 1 2 to 3 4 of the lower receiver sight glass If itis notat the proper level add or remove to bring it to the proper level Refrigerant level should not ap pearin the uppersight glass as this would indicate an overcharge Backseat the suction service valve Close the vapor valve on the refrigerant drum and note weight Re move the manifold gauge set and replace all valve caps 4 8 CHECKING FOR NONCONDENSIBLES To check for noncondensibles proceed as follows a b Check saturation pressure as it corresponds to the Stabilize system to equalize pressure between the suction and discharge side of the system Check temperature at the condenser and receiver Check pressure at the filter drier inlet service valve condenser receiver temperature using the Temperat ure Pressure Chart Table 4 4 If gauge reading is 3 psig 0 20 bar or more than the saturation pressure in step d noncondensibles are present Rem
56. arm prefix and 15 the alarm generated When the alarms are viewed this will be the number If no alarms are present the display will show first alarm to be shown the 5 dun Mrs arrow keys at the same time and hold for seconds If multiple alarms are present the user can 3 24 Alam Clear scroll through each alarm by pressing the AUTO key Whenthe end ofthe alarm listis reached the display will show Press VENT to scroll backward from the latest oe ee e in min using the to scroll back only the alarm code will be shown the alarm time will not be shown If the 3 3 TROUBLESHOOTING The user may clear inactive alarms using the Micromate control panel keypad Refer to paragraph 3 2 1 AUTO key is held down for five seconds while is displayed all inactive alarms are cleared A listing of General procedures for system troubleshooting are alarm codes is provided in Table 3 2 provided in Table 3 3 12 09 3 1 T 302 12 High Voltage The battery voltage is Check repair or re greater than 32 volts place alternator Low Voltage The battery voltage is less than 17 volts Return Air Probe Failure Suction Pressure Transducer F ailure Low Pressure Shutdown Discharge Pressure Transducer F ailure T 302 Table 3 2 Alarm Codes ALARM TITLE CAUSE REMEDY CONTROLLER NO RESPONSE Coil temperature is less than 32 F and the compressor is op erating
57. ator will be allowed to set the setpoint temperature The value can be modified in degrees with the up and down keys to a value between 60 F and 80 F 12 09 2 7 T 302 Table 2 4 Parameter Codes Continued code P20 Compressor Hours This is the number of hours of operation that the compressor has run with the High clutch energized in thousands P21 Compressor Hours This is the number of hours of operation that the compressor has run with the Low clutch energized in hundreds tens and ones P22 Evaporator Hours This is the number in thousands of hours of operation with the evaporator High fans energized P23 Hours Low This is the number in hundreds tens and ones of hours of operation with the evaporator fans energized P24 Maintenance 1Hour This is the value of compressor hours high P 20 at which maintenance alarm High 1 will be activated This value can be modified by the up and down arrow keys If both high and low values are zero the alarm is disabled P25 Maintenance 1Hour is the value of compressor hours low P21 at which maintenance alarm Low 1 will be activated This value can be modified by the up and down arrow keys If both high and low values are zero the alarm is disabled 26 Maintenance 2 Hours This is the value of evaporator fan hours high P 22 at which maintenance High alarm 42 will be activated This value can be modified by the up and down ar row keys If both high and lo
58. ature on shaft usin key tight en mounting bolt to 20 ft lbs 8 Perform check of the air gap between the inside face of the armature and the mating face of the rotor The airgap should be measured with a minimum of 30 psig 2 04 bar in the crankcase A preliminary check may be performed before the crankcase is pressur ized but a final check must be performed before the clutch is operated The gap should be between 0 030 and 0 060 inch 7 62 to 15 24 mm Loosen each of the three lock nuts with a 7 16 box wrench while holding the jacking screws with a 1 8 hex socket wrench r Back off the three jacking screws until they do not touch the armature plate s Turn the jacking screws clock wise until they make contact with the armature plate and then one and one half more turns after contact t Measure the initial clearance the gap should be between 030 and 060 All three set screw locations should be very close in clearance dimensions With the clearance set hold each set screw while tightening the lock nuts to 7 ft lbs v Reconnect wiring and test clutch operation 4 14 4 Compressor Oil Level To check and if required correct the compressor oil level do the following a Operate the coach for at least one half hour at fast idle speed with the temperature controls at the cool est setting and the compressor fully loaded It may be necessary to pre heat the coach and or operate
59. ck compressor oil level refer to paragraph 4 14 4 Add or remove oil if necessary p Check compressor unloader operation refer to para graph 4 14 5 q Backseat compressor service valves r Remove manifold gauge set refer to paragraph 4 3 or paragraph 4 3 1 4 14 3 Transferring Compressor Clutch To remove a clutch see Figure 4 14 from a compressor and install on a replacement compressor do the following Compressor Armature Seal Cover Spacer Nuts Coil Retaining Capscrew R otor ockwasher 3 8 Washer Rotor Nut Figure 4 14 Compressor Clutch Place main battery disconnect switch in OFF position and lock Tag and disconnect wiring to the clutch Remove tension on drive belts remove drive belts Remove the armature as a complete assembly by re moving the retaining capscrew lockwasher and spe cial 3 8 washer from the compressor crankshaft Use special tool CTD P N 07 00240 01 to prevent crankshaft rotation Install a 7 8 14 x 4 CTD P N 07 00381 00 caps crew into the center hole of the armature assembly and use it as a jacking bolt to remove the armature 12 09 4 11 Use tool CTD P N 07 00240 01 as instep a to vent crankshaft rotation Using special tool CTD P N 07 00242 01 remove the rotor nut and rotor Retain original key Noting the position of the wire remove the three bolts holding the coil to the compressor Remov
60. discharge lines into the condenser tubes The condenser fan circulates surrounding air which is ata temperature lower than the refrigerant over the outside of the condenser tubes Heat transfer is established from the refrigerant inside the tubes to the condenser air flowing over the tubes The condenser tubes have fins designed to improve the transfer of heat from the refrigerant gas to the air this removal of heat causes the refrigerant to liquefy thus liquid refrigerant leaves the condenser and flows to the receiver The receiver serves as a liquid refrigerant reservoir so that a constant supply of liquid is available to the evaporators as needed and acts as a storage space when pumping down the system The receiver is equipped with sight glasses to observe the refrigerant level and moisture content The refrigerant leaves the receiver and passes through the subcooler heat exchanger if so equipped and filter drier The sub cooler transfers heat from the liquid to the air in the same manner as the condenser coil and the heat exchanger if so equipped further cools the liquid by transferring heat to the suction gas These components improve efficiency by delivering the liquid to the expansion valve in a subcooled state The filter drier contains an absorbent that keeps the refrigerant clean and dry From the filter drier the liquid refrigerant then flows through the liquid line solenoid valve to the thermostatic expansion valve
61. e 1 7 Logic Board 1 6 CONTROL PANEL Driver Controller 12 09 1 2 3 TRANSICOLD Display 4 TEMPERATURE Inside Outside DOWN Button decrease selection Button UP Button increase selection 5 ON OFF Button Figure 1 8 Micromate Control Panel Driver Controller 1 9 T 302 1 7 CONTROL PANEL Full Function Controller Display DOWN Button decrease selection UP Button increase selection VENT Only Button AUTO Button Automatic Control COOLING Only Button HEAT Only Button FAN SPEED Button FRESH AIR Button Not Applicable This System TEMPERATURE Inside Outside Button 11 ON OFF Button Figure 1 9 Micromate Control Panel Full Function Controller 18 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS a Refrigerant Charge R 22 16 Ib 7 26 kg R 134a 20 Ib 9 09 kg b Compressor 056 145 Ibs Compressor No of Cylinders Weight Dry With Clutch Oil Charge Oil Level Level in sight glass between Min Max marks on compressor crankcase Approved Compressor Oils R 22 Units Calumet Refining Co 8030 Texaco WF68 Witco 4GS Suniso R 134a Units Castrol SW68C Mobil EAL Arctic 68 ICI Emkarate RL68H 66 kg 5 5 pints 2 6 liters T 302 c Thermostatic Expansion Valve R 22 Units S uperheat Setting 12 3 F 5 to 8 C MOP Setting 95 5 7 psig 6 5 0 48 bar R 134a Units S uperheat Setting 12 3 F 5 to 8 C MOP Setting 53
62. e 5 26 Wiring Schematic Control Circuit 68RM35 604 50 51 58 74 5 27 Figure 5 27 Wiring Schematic Power Circuit 68RM35 604 50 51 58 74 5 28 Figure 5 28 Wiring Schematic Control Circuit 688RM35 604 52 80 5 29 Figure 5 29 Wiring Schematic Power Circuit 68RM35 604 52 80 5 30 Figure 5 30 Wiring Schematic Control Circuit 68RM35 604 54 62 78 5 31 Figure 5 31 Wiring Schematic Power Circuit 68RM35 604 54 62 78 5 32 Figure 5 32 Wiring Schematic Control Circuit 68RM35 604 55 68 84 5 33 Figure 5 33 Wiring Schematic Power Circuit 68RM35 604 55 68 84 5 34 Figure 5 34 Wiring Schematic Control Circuit 68RM35 604 59 69 75 85 5 35 Figure 5 35 Wiring Schematic Power Circuit 68RM35 604 59 69 75 85 5 36 Figure 5 36 Wiring Schematic Control Circuit 68RM35 604 63 70 79 86 5 37 Figure 5 37 Wiring Schematic Power Circuit 68RM35 604 63 70 79 86 5 38 Figure 5 38 Wiring Schematic Control Circuit 68RM35 604 66 82 5 39 Figure 5 39 Wiring Schematic Power Circuit 68RM35 604 66 82 5 40 Figure 5 40 Wiring Schematic 68RM35 604 67
63. e every other bolt from the seal cover of the new compressor in the same manner as the original compressor Mount coil assembly with the wire in the same orientation as itwas mounted on the original compressor Tighten the mounting bolts to 45 50 ft Ibs 5 53 6 92 mkg Mountthe rotor on the shaft S eat rotor to the hub using the rotor nut Be sure pulley turns freely without binding Tighten rotor nut by first noting torque neces sary to start the nut on the hub and then adding 50 ft 105 6 92 of torque NOTE A 3 point shim less armature plate may be in stalled in place of the shim pack armature plate Three adjusting screws installed in the spring plate of the 3 point shim less armature plate eliminate the need for separate shims used with the shim pack armature plate Arma ture to rotor clearance is the same in both designs 4 14 3 a Shim Pack Compressor Clutch Original j Install armature on shaft using original key and tight en mounting bolt to 20 ft lbs 2 8 Perform a check of the air gap between the inside face of the armature and the mating face of rotor The airgap should be measured with a minimum of 50 psig 3 4 bar in the crankcase A preliminary check may be performed before the crankcase is pressur ized but a final check must be performed before the clutch is operated The gap should be between 0 030 and 0 060 inch 7 62 to 15 24 mm If required re move the s
64. e switch c Start the system and run in cooling Stop the unit when suction reaches a slight vacuum 1 2 hg Frontseat the compressor suction service valve to trap refrigerantin the high side ofthe system between the compressor suction service valve and the filter drier inlet valve Wait 5 minutes to verify that system remains in a vacuum If system pressure rises above a vacuum open the compressor suction service valve and repeat steps c and d until the system re mains in a vacuum e Service or replace necessary components f Leak check connections and replace filter drier Re fer to paragraph 4 5 Energize the Liquid Line Solenoid Valve LS V using an external power source 24 VDC Using refrigeranthoses designed for vacuum service evacuate and dehydrate the low side ofthe system by connecting a vacuum pump to the center connection of manifold gauge set Evacuate system to 500 mi crons Close off pump valve isolate vacuum gauge And ap pump Wait 5 minutes to verify that vacuum olds Recharge low side with R 134a to 20 to 30 PSIG or with R 22 to 45 to 60 PSIG by admitting vapor from the refrigerant cylinder j Re connect the suction pressure transducer and re move the low pressure switch jumper If required clear any alarms that have been generated during this procedure Open service valves and check refrigerant level Re fer to paragraph 4 7 1 b T302 Filter Drier Outlet Serv
65. elay 7 Fuse 1 Control Power 19 Terminal Block 8 Fuse Spare 20 CB7orF7 Relay Board Outputs 9 Power Relay 21 CB13 or F13 Relay Board Outputs 10 Floor Blower Relay 22 1 Boost Pump 11 Fault Relay ACSL 23 Service Port Micro Processor 12 Evaporator Fan Speed Relay 24 Micromate Control Panel Figure 1 4 Control Panel Typical T 302 1 6 12 09 1 3 RELAY BOARD 12 00371 00 O O 2 O a Relays K1 K2 K7 K8 K13 K14 K15 K18 K19 E nergizes evaporator fans in low speed E nergizes evaporator fans in high speed not energized in low speed E nergizes condenser fans in low speed E nergizes condenser high speed not energized in low speed E nergizes the A C clutch and liquid line solenoid valve nergizes unloader 1 nergizes unloader 2 E nergizes the fault light output E nergizes the boost pump and heat valve b Connectors 2 JP4 12 09 J umpers Logic board connector Boost pump clutch liquid line solenoid valve and fault output Floor blower relay Unloaders 1 amp 2 Evaporator fan relays 24 Volt power input Condenser fan relays c
66. emperature thermocouple in contact with the suction tube and parallel to the TXV bulb and then secure loosened clamp making sure both bulb and thermocouple are firmly secured to suction line pus Uie 4 11 Reinstall insulation around the ulb Connect an accurate low pressure gauge to the low pressure port Figure 1 10 23 Start bus and run on fast idle until unit has stabilized about 20 to 30 minutes NOTE When conducting this test the suction pressure must be at least 6 psig 0 41 bar below the ex pansion valve maximum operating pressure MOP Refer to paragraph 1 8 for MOP From the appropriate temperature pressure chart Table 4 4 determine the saturation temperature corresponding to the evaporator outlet pressure Note the temperature ofthe suction gas atthe expan sion valve bulb Subtract the saturation temperature from this temperature The difference is the super heat of the suction gas The superheat may cycle from a low to high reading Monitorthe superheattaking readings every 3 5 min utes for a total of 5 6 readings Calculate the super heats add the readings and divide by the number of readings taken to determine average superheat Re ferto paragraph 1 8 for superheat setting Ifsuperheatis not within tolerance replace the valve T302 4 13 REPLACING RETURN AIR FILTERS The return air filters are located behind the return air grill inside the vehicle The filters should
67. ept for the evaporator fans and heat and the system is locked out until the pow er is cycled or the alarm is reset 12 09 Table 3 2 Alarm Codes Continued ALARM TITLE CAUSE REMEDY CONTROLLER NO RESPONSE High Discharge Pressure High discharge pres discharge The clutch is de ener sure switch open or pressure transducer gized for the minimum wiring defective reading wiring or off time The condenser cause of high dis and evaporator fans will charge pressure Re remain running during fer to section 3 3 3 this period After the compressor cycles off three times in 30 min utes all outputs will be de energized except for the evaporator fans and heat and the system is locked out until the er is cycled or the alarm is reset Breaker Trip Alarm A breaker on the relay Check breakers for Alarm will be generated board has tripped ora tripped device Repair fan relay has failed short and reset break Evaporator Fan Overload fan over connector is Alarm will be generated load jumper is open plugged in or repair wiring Condenser Fan Overload Condenser fan over Ensure connector is Alarm will be generated load jumper is open plugged in or repair wiring NN 1 2 5 Maintenance Alarm 1 The compressor hour Reset mainte Alarm will be generated meter is greater than hour meter the value in Mainte nance Hour Meter 1
68. er device to the compressor and re move compressor from the coach through the access door NOTES 1 Service replacement compressors are sold without service valves Valve pads are installed in their place The optional unloaders are not supplied as the cylinder heads are shipped with plugs The customer should retain the original unloader valves for use on the replacement compressor 2 The piston plug that is removed from the replacement compressor head must be installed in the failed compressor if returning for warranty or core credit T 302 3 Do not interchange allen head capscrews that mount the piston plug and unloader they are not interchangeable Check oil level in service replacement compressor Refer to paragraphs 1 8 and 4 14 4 MAX MIN Q uum Bottom Plate Oil Drain Plug Oil Level Sight Glass Oil Pump O ring Discharge Service Valve Service Port Electric Unloader Valve Suction Service Valve Charging Port Suction Service Valve Clutch Oil Fill Plug Shaft Seal Reservoir 7 8 9 10 11 12 13 Figure 4 12 Compressors Remove the three socket head capscrews from the cylinder head s that have unloader valves installed See Figure 4 13 Remove the unloader valve and by pass piston assembly keeping the same capscrews with the assembly The original unloader
69. er if fitted Heater Coil Assembly Evaporator Fan Motor 1 Evaporator Fan Housing Roadside 17 Figure 1 2 Unit Assembly Back View 1 2 3 Evaporator System The evaporator system includes the evaporator coil fan and motor assemblies liquid suction heat exchanger if so equipped heater coil assembly a thermostatic expansion valve and condensate drain connections The thermostatic expansion valve meters the flow of refrigerant entering the evaporator coil The evaporator coil provides heat transfer surface for transferring heat from air circulating over the outside the coil to refrigerant circulating inside the tubes thus providing cooling The liquid suction heat exchanger absorbs heat from the liquid refrigerant further heating the suction n decreasing the possibility of liquid refrigerant from returning to the compressor The heating coils provide heat transfer surface for transferring heat from engine coolant water circulating inside the tubes to air T 302 1 4 circulating over the outside surface of the tubes thus providing heating The fans circulate the air over the coils The air filters remove dirt particles from the air before it passes over the coils A heat valve controls the flow of engine coolant water to the heating coils upon receipt of a signal from the controller The condensate drain connections provide a means for connecting tubing for disposing of condensate collected on the evaporator co
70. er s Start the bus and run in cooling lower set point if re quired to ensure system remains in full speed cooling Locate the unloader connector at the compressor Observe manifold suction gauge while unplugging the connector Pressure should decrease 3 to 5 psi 0 2 to 0 4 bar when the unloader is unplugged and increase the same amount as the plug Is recon nected Repeat test for second unloader if fitted f If pressures do not react as described check unload er coil or repair unloader mechanism as required When testing is complete reconnect transducer and unloader connectors and remove manifold gauge set Disconnection of the suction pressure transducer will cause 15 alarm Once the transducer is recon nected the alarm will go to inactive and can then be cleared 4 15 TEMPERATURE SENSOR CHECKOUT a An accurate ohmmeter must be used to check resist ance values shown in Table 4 1 5 Q 12 09 b Due to variations and inaccuracies in ohmmeters Table 4 1 Temperature Sensor Resistance thermometers or other test equipment a reading vi ve a sensor be ue would usually be much higher or lower than the value given in Table 4 1 20 least one sensor lead must be pe sa from pla Pt vele Me A oa lt 01 of determining Ee 0 212 2 c ci p Meler 3 X 16 1530 80
71. erant Lines Engine Coolant P iping Air Conditioning Unit Condenser Air Flow Control Harness mounted compressor To complete the system the air conditioning and heating equipment interfaces with electrical cabling refrigerant piping engine coolant piping for heating duct work and other components furnished by the bus manufacturer Information on the compressoris provided in separately bound manuals Refer to Table 1 2 Driver Control P anel Fresh Air Connection Power Harness amp Power Relay Battery Alternator Figure 1 1 A C Component Identification 1 2 GENERAL DESCRIPTION 1 2 1 Air Conditioning Unit Assembly Operation of the units is controlled automatically by a microprocessor based Micromax Controller which maintains the vehicle s interior temperature at the desired set point The unit assembly see Figure 1 2 and Figure 1 3 includes the condensing system equipment evaporator system equipment Micromax controller and a fresh air connection Components are accessible by opening the inside or outside covers Descriptions of the systems are provided in the following sub paragraphs 1 2 2 Condensing System The condensing system includes the condenser coil liquid suction heat exchanger if so equipped fan and motor assemblies filter drier receiver with sight glasses and moisture indicator liquid line solenoid valve discharge line check valve discharge line connection service valves fusible plug a
72. erature read ing 11 Setpoint may be changed by pressing the UP DOWN arrow button The UP button will increase the setpoint temperature and the DOWN button will de crease the setpoint temperature 12 For additional Micromate operating data refer to paragraph 2 4 2 1 3 Self Test and Diagnostics Check for Errors and or Alarms Self test of the main Logic Board electrical circuit is automatically initiated when the system is powered up Ifthere is error inthe circuit an alarm will be indicated by flashing LED s on the Logic Board If a Micromate is connected to the Logic Board the error code can also be read on the display If there are no errors in the circuit system will operate normally and flash the status LED at a one second interval During normal operation the Logic Board monitors system operating parameters for out of tolerance conditions If an out of tolerance condition occurs ALARM will be indicated through the code LED oron the Micromate display Refer to section 3 for definition of system errors and alarms and general troubleshooting procedures T 302 2 1 4 Stopping Placing the ON OFF switch in the OFF position or pressing the Micromate ON OFF button will stop the system operation by removing power to the Logic Board Note If OEM switches at the dash are supplied they will override control unless the J 3 plug on the logic board is disconnected 2 2 PRE TRIP INSPECTION After starting system allow
73. f the evaporator and condenser fans Do not open the condenser fan grille or evaporator access panels before turning power off and disconnecting and securing the power plug Be sure power is turned off before working on motors controllers solenoid valves and electrical control switches Tag circuit breaker and power supply to prevent accidental energizing of circuit Do not bypass any electrical safety devices e g bridging an overload or using any sort of jumper wires TO AIR the system should be diagnosed and any necessary repairs performed by qualified service personnel When performing any arc welding on the unit disconnectall wire harness connectors from the modules in the control box Do not remove wire harness from the modules unless you are grounded to the unit frame with a static safe wrist strap case of electrical fire open circuit switch and extinguish with never use water 12 09 Safety 1 T 302 SPECIFIC WARNING AND CAUTION STATEMENTS The statements listed below are applicable to the refrigeration unit and appear elsewhere this manual These recommended precautions must be understood and applied during operation and maintenance of the equipment covered herein SPECIFIC WARNINGS AND CAUTIONS 44 WARNING Be sure to observe warnings listed in the safety summary in the front of this manual before performing maintenance on the hvac system AX WARNING Read the entire procedure before beginn
74. fety device open Check Tighten Replace Check Check R eplace 4 15 or 4 16 Check Check Defrost coil Clean Clean R eplace Repair R eplace Replace Repair R eplace Repair R eplace Clean R eplace Clean Defrost Check R eplace 1 12 Replace Replace 4 12 Replace Replace 4 12 Clean Check R eplace Check Clean Open Repair R eplace Repair R eplace Check R eplace Replace Repair R eplace 1 12 Continuous Heating Reheat coolant solenoid valve stuck open 12 09 3 5 T 302 SECTION 4 SERVICE WARNING Be sure to observe warnings listed the safety summary the front ofthis manual before perform ing maintenance on the hvac system WARNING Read the entire procedure before beginning work Park the coach on a level surface with parking brake applied Turn main electrical disconnect switch to the off position NOTE Following completion of all maintenance or service activities the alarm queue should be cleared of any origi nal alarms and any alarms generated during service Refer to paragraph 3 2 1 NOTE To avoid damage to the earth s ozone layer use a refrigerant recovery system whenever removing refriger ant When working with refrigerants you must comply with all local government environmental laws 4 1 MAINTENANCE SCHEDULE REFERENCE SYSTEM SECTION a Maintenance X Pre trip Inspection after starting 2 2 X tension and condition of V belt None
75. fficient nitrogen to raise system pressure to 150 to 200 psig 10 21 to 13 61 bar Check for leaks The recommended procedure for finding leaks in a system is with an electronic leak de tector Testing joints with soap suds is satisfactory and may be necessary under conditions when an electronic leak detector will not function correctly b O 12 09 4 5 Remove test gas and replace filter drier f Evacuate and dehydrate the system Refer to para graph 4 6 0 Charge the unit Refer to 4 7 h Ensure that a Logic Board self test has been per formed and that there are no errors or alarms indi cated Refer to paragraph 2 1 3 46 EVACUATION AND DEHYDRATION 4 6 1 General The presence of moisture in a refrigeration system can have many undesirable effects The most common are copper plating acid sludge formation freezing up of metering devices by free water and formation of acids resulting metal corrosion A triple evacuation R efer to paragraph 4 6 3 should be performed after a major system repair compressor evaporator or condenser replacement A one time evacuation Refer to paragraph 4 6 4 should take place aftera minorsystem repair replacement of a solenoid valve or a filter drier 4 6 2 Preparation NOTE Using a compound gauge for determination of vacuum level is not recommended because of its inherent inaccuracy NOTE Never evacuate an open drive compres
76. g Close the cylinder valve and slowly open bleed off valve The switch should open no continuity with in required cut out tolerance Open cylinder valve and increase pressure by closing the bleed off valve As pressure in creases switch should close continuity within re quired cut in tolerance 12 09 4 7 g Replace or re install switch as required nect wiring 4 10 FILTER DRIER 4 10 1 To Check Filter Drier The filter drier see Figure 4 8 must be changed if the drier is partially restricted or service has been performed on the refrigerant system Check for a restriction by feeling the inlet and outlet lines of the filter drier If the outlet side feels cooler than the inlet side then the filter drier should be changed 4 5 Filter Drier Filter Drier Outlet Service Valve 1 Filter Drier Inlet Service Valve 2 Valve Service Port 3 Flare Nut Figure 4 8 Filter Drier Removal 4 10 2 To Replace Filter Drier a Perform a low side pump down Refer to paragraph 4 4 1 steps a to c b Turn the driver s A C switch to OFF position Frontseat the filter drier outlet service valve and place a new filter drier near the unit for immediate installation Remove two screws securing the filter drier clamp Remove the filter drier clamp WARNING The filter drier may contain liquid refriger ant Slowly loosen the flare nuts to avoid re frigerant contact
77. hen this configuration is removed the display will show temperatures in F When not removed the display will show temperatures in C Reheat When this configuration is removed reheat mode will use the PI algorithm to vary the duty cycle of the heat valve If itis not removed the heat valve will be on constantly Low Ambient Lockout When this configuration is removed the compressor clutch will disen gage at 25 F With this configuration in place the compressor will disengage at 45 F T 302 4 18 12 09 Table 4 4 R 22 Temperature Pressure Chart Temperature Pressure 6 Kgem Bar 48 476 48 o 814 72 8 16 1025 721 7 07 20 1831 832 816 27 M5 1019 100 1 07 1 17 TETA 86 36 1565 1311 1286 m 34131 240 2353 156 69 4155 2922 28 65 Bar _ 04 16 28 41 48 56 63 EUN 79 88 297 105 114 124 E ECJ 1277 189 2 01 214 2 27 2 41 2 54 2 69 283 2 99 34 33 3 46 3 63 3 81 3 99 12 09 4 19 302 Table 4 5 R 134a Temperature Pressure Chart r 245 033 Lus p per pue poz m pepe wu Lus pum s po Las cm 66 1 082 Pm om
78. ial such as dirt scale or sludge in the coolant system or improper voltage to the coil Service of the valve may include replacement of the internal parts see Figure 4 18 or replacement of the entire valve There are only three possible valve malfunctions coil burnout failure to open or failure to close 4 20 1 Reheat Coolant Valve Malfunctions Coil Retaining Screw Nameplate Coil Housing Assembly Enclosing Tube amp Bonnet Assembly Kick O ff Spring 6 Plunger 7 Closing Spring 8 Diaphragm 9 O Ring 10 Valve Body Figure 4 18 Reheat Coolant Valve Assembly Coil burnout be caused Improper voltage 2 Continuous over voltage more than 10 under voltage of more than 15 3 Incomplete magnetic circuit due to the omission of the coil housing or plunger 4 Mechanical interference with movement of plunger which may be caused by a deformed enclosing tube 12 09 b Failure to open may be caused by 1 Coil burned out or an open circuit to coil connections 2 Improper voltage 3 diaphragm 4 Defective plunger or deformed valve body assembly c Failure to close may be caused by Defective plunger or deformed valve body assembly 2 Foreign material in the valve 4 20 2 Replacing the Coil NOTE Itis not necessary to drain the coolant from the system a Place the rear control switch in the OFF position b Disconnect wire leads
79. ice Valve Manifold Gauge Set Filter Drier Filter Drier Inlet Service Valve Thermistor Vacuum Gauge Vacuum Pump Refrigerant Cylinder Reclaimer Thermostatic Expansion Valve Liquid Solenoid Valve Figure 4 4 Low Side Pump Down Connections 4 4 2 Refrigerant Removal From An Inoperative Compressor To remove the refrigerant from a compressor that is not operational do the following a O Attach manifold gauge set as shown Figure 4 5 and isolate the compressor by front seating the suc tion and discharge valves Recover refrigerant with a refrigerant reclaimer If the discharge service valve port is not accessible it will be necessary to recover refrigerant through the suc tion service valve port only Service or replace components as required and leak check the compressor Using refrigeranthoses designed for vacuum service connecta vacuum pump to center connection of man ifold gauge set Evacuate system to 500 microns Close off pump valve isolate vacuum gauge and stop pump Wait 5 minutes to verify that vacuum holds Once vacuum is maintained recharge low side with R 134a to 20 to 30 PSIG or with R 22 to 45 to 62 PSIG i admitting vapor from the refrigerant cylin der Backseat compressor service valves and discon nect manifold gauge set Check refrigerant level Refer to paragraph 4 7 1 It may be necessary to clear any alarms tha
80. ils during cooling operation 12 4 Compressor Assembly The compressor 2 includes the refrigerant compressor clutch assembly suction and discharge service valves high pressure switch low pressure switch suction and discharge servicing charging ports and electric solenoid unloaders 12 09 CURBSIDE CS ROADSIDE RS a m SOPLOR OP GO d ERR tf co TE Model Serial Number Plate 6 Electrical Control Panel See Figure 1 4 Liquid Line Solenoid Valve Thermostatic Expansion Valve TXV Roadside Blower Housing 5 Air Filter Evaporator Coil Curbside Blower Housing 5 6 7 Figure 1 3 Unit Assembly Inside View Typical The compressor raises the pressure and temperature of the refrigerant and forces it into the condenser tubes The clutch assembly provides a means of belt driving the compressor by the bus engine The suction and discharge service valves enable servicing of the compressor Suction a
81. ing work Park the coach on a level surface with parking brake applied Turn main electrical disconnect switch to the off position 4 WARNING Do Not Use A Nitrogen Cylinder Without A Pressure Regulator AX WARNING Do Not Use Oxygen In Or Near A Refrigeration System As An Explosion May Occur A WARNING The Filter drier May Contain Liquid Refrigerant Slowly Loosen The Flare Nuts To Avoid Re frigerant Contact With Exposed Skin Or Eyes WARNING Extreme Care Must Be Taken To Ensure That All The Refrigerant Has Been Removed From The Compressor Crankcase Or The Resultant Pressure Will Forcibly Discharge Compressor Oil 44 WARNING Be careful of remaining hot coolant in the hoses when disassembling 44 CAUTION Do not under any circumstances attempt to service the microprocessor Should a problem develop with the microprocessor replace it CAUTION To preventtrapping liquid refrigerantin the manifold gauge set be sure setis brought to suc tion pressure before disconnecting 44 CAUTION Use care when checking manipulating wires plugs attached to the Logic Board Damage to the board or wiring harness can occur T 302 Safety 2 12 09 TABLE OF CONTENTS PARAGRAPH NUMBER Page SPECIFIC WARNING AND CAUTION STATEMENTS ii SPECIFIC WARNINGS AND CAUTIONS ii CONTENTS ta
82. ion ofthe filter drierforservice The ambient temperature sensor measures ambient temperature and sends an electrical signal to the controller T 302 Table 1 1 Model Number Chart MODEL REFRIGERANT CONTROL CONDENSER EVAPORATOR FILTER NUMBER _ HEAT EXCHANGER MOTOR MOTOR 68RM35 104 40 R 22 NO Reheat Permanent Magnet Magnet Disposable w R esistor 68RM35 104 41 R 22 NO Wound Field WoundField Cleanable 68RM35 104 42 R 22 NO Wound Field WoundField Cleanable 68RM35 104 43 R 22 NO Permanent Magnet Permanent Magnet Cleanable 68RM35 104 45 R 22 NO Permanent Magnet Permanent Magnet Cleanable 68RM35 604 41 R 134A YES Wound Field Permanent Magnet Disposable 688 35 604 42 R 134A YES Permanent Magnet permanent Magnet Cleanable 688 35 604 43 R 134A YES perman m Magnet Pem nen Magnet Permanent Magnet Customer 68RM35 604 44 R 134A YES Permanent Magnet Supplied 68RM35 604 45 134 YES perne a sabie G6RM35 604 50 R 134A YES Cleanable G6RM35 604 51 R 134A YES Cleanable 68R 35 604 52 R 134A YES Brushless Cleanable 68RM35 604 53 R 134A YES Permanent Magnet permanent Magnet Disposable YES Permanent Magnet Reheat w R esistor 68RM35 604 54 R 134A YES 6BRM35 604 55 R 134A YES Cleanable 68RM35 604 56 R 134A YES Wound Field Wound Field Cleanable 688 35 604 58 R 134A YES Cleanable R W Permanent Magnet Cleanable
83. ision 1 3 and newer Otherwise P 35 will not be active and set point temperature will only be displayed as default 40 Enable Hidden Alarm This value determines if alarms A33 and A34 are displayed When the value is OFF alarms A33 and A34 will not be displayed When the value is ON alarms A33 and A34 will be displayed Fresh Ar Damper Defrost Operation This value determines if the defrost switch will override the Micromate control ler If the parameter is ON the defrost switch will initiate unit defrost whenever it senses a need for defrosting the Micromate display will shut off in defrost If the parameter is OFF the Micromate display will continue to operate and over ride the defrost switch T 302 2 8 12 09 SECTION 3 TROUBLESHOOTING AX CAUTION Do not under any circumstances attempt to service the microprocessor Should a problem develop with the microprocessor replace it 3 1 SELF DIAGNOSTICS that the Logic Board STATUS and CODE LED s see A self test performed bythe Micromax Logie Board 1057 fesh The each time the board is powered up Errors if any will be indicated and the unit will not be allowed to start where is the error prefix and is the error error codes can be read by counting the number of times number Table 3 1 Error Codes WANE DESCRIPTION Data Memory Logic board data memory failure Program Memory Logic board program memory fail
84. it will display CL If it is open circuited it will display OP Temperature Ambient Temperature This value is the outside temperature measured the ambient temperature sensor If the sensor is shorted it will display CL If itis open circuited it will dis play OP Suction Line Not used Temperature 5 Suction Pressure This value is the suction pressure measured by the suction pressure transduc er If the sensor is shorted it will display CL If it is open circuited it will display OP Discharge Pressure This value is the discharge pressure measured by the discharge pressure transducer If the sensor is shorted it will display CL and if it is open circuited it will display OP S uperheat Not used Analog Set Point Not used Temperature A C Control Window This is the number of degrees F above setpoint at which the unloaders will be 1 both energized This value can be modified between 0 and 10 degrees F The default value is 1 degree F P10 Control Window This is the number of degrees above AC control window one at which the 2 first unloader will be energized This value can be modified between 0 and 10 degrees F The default value is 1 degree F 11 A C Control Window This is the number of de F above AC control window two at which the 33 evaporator fan speed will be set low This value can be modified between 0 and 10 degrees F The default value is 1 degree F He P12 at Control Windo
85. ith a Micromate as the operators control there is no wiring to the Logic Board J 3 connector instead the Micromate is hard wired to the Logic Board connector 2 When the micromate is used for service or diagnostic purposes itis wired in the Same manner as shown for drivers panel use thru the optional Service Port Contact your Carrier Transicold service en ale or call the technical hot line at 800 450 2211 for questions related to the schematic for your specific model 12 09 5 1 T 302 joi gt O a xi 77 Ai a SYMBOLS CONNECTOR TERMINAL GROUND WIRING ON BOARD FACTORY WIRING OEM WIRING GROUND STUD POWER STUD CONNECTOR NORMALLY CLOSED CONTACT NORMALLY OPEN CONTACT CONNECTOR POSITON A LAMP DIODE FUSE COIL MOTOR EF PRESSURE SENSOR LED ASSEMBLY PRESSURE SWITCH TEMPERATURE SENSOR MANUAL RESET BREAKER RELAY COIL MANUAL SWITCH POLY SWITCH TEMPERATURE SWITCH MULTI PLEX MODULE RIBBON CABLE OVERLOAD RESISTOR SYMBOL ATS BPS CB CFR CL CM COL CSR DPT EFR EM EOL ESR F HPS K1 K2 K7 K8 K13 K14 K15 K15 K17 K18 K19 K20 K21 K22 K23 K24 LPS LSV PR R1 RAS RCV SPT UV WTS SYMBOL lt lt lt CU U II LEGEND DESCRIPTION AMBIENT TEMPERATURE SENSOR BOOST PUMP SIGNAL CIRCUIT BREAKER CONDENSER FAN REALY COMPRESSOR CLUTCH CONDENSER FAN MOTOR
86. ix armature spacer nuts and spacer Add or remove shims to adjust gap Reinstall spacer nuts and tighten to 7 8 ft lbs 1 0 to 1 1 Reconnect wiring and test clutch operation 4 14 3 b 3 Point Shim less Compressor Clutch j k Install armature on shaft using original key and tight en mounting bolt to 20 ft Ibs 2 8 mkg Perform a check of the air gap between the inside face of the armature and the mating face of the rotor The air gap should be measured with a minimum of 30 psig 2 04 bar in the crankcase A may be performed before the crankcase is pressur ized but a final check must be performed before the clutch is operated The gap should be between 0 030 and 0 060 inch 7 62 to 15 24 mm Loosen each of the three lock nuts with a 7 16 box wrench while holding the jacking screws with a 1 8 hex socket wrench m Back off the three jacking screws until they do not n touch the armature plate Turn the jacking screws clock wise until they make contact with the armature plate and then one and one half more turns after contact T302 Measure the initial clearance the gap should be between 030 and 060 Allthree set screw locations should be very close in clearance dimensions p With the clearance set hold each set screw while tightening the lock nuts to 7 ft lbs q Reconnect wiring and test clutch operation 4 14 3 3 Point Shim less Compressor Clutch j Install arm
87. kseated positions the suction or discharge gauge through the valve The valve should always be port is open to both the compressor and the line 12 09 4 1 T 302 TO DISCHARGE OR FROM SUCTION LIN Stei SY PORT COMPRESSOR VALVE STEM CAP aN SERVICE PORT R 22 VALVE STEM Service Valve Backseated counterclockwise D ACCESS VALVE Figure 4 1 Suction or Discharge Service Valve 4 3 INSTALLING MANIFOLD GAUGE SET A manifold gauge set Figure 4 2 can be used to determine system operating pressures add charge equalize or evacuate the system Service Valve Frontseated clockwise ACCESS VALVE R 134a Low Pressure High Pressure Hand Valve F rontseated Hand Valve O pen A Connection to C Connection to Either Low Side of System Vacuum Pump Refrigerant B Connection to High Side of System Figure 4 2 Manifold Gauge Set When the suction pressure hand valve is frontseated turned all the way in the suction low pressure read When the discharge pressure hand valve is frontseated discharge high pressure can be read When both valves are open turned counterclockwise high pressure vapor will flow into the low side When only the low pressure valve is open the system can be charged or evacuated To install a manifold gauge set do the following refer to Figure 4 4 Figure 4 5 or Figure 4 6 as applicable
88. l Valve Parts 4 16 4 20 4 Replacing the Valve Assembly 4 16 4 21 LOGIC BOARD REPLACEMENT 4 17 ELECTRICAL 2222 5354 kx Gar IR ac at Ea 5 1 5 1 INTRODUCTION AS 5 1 12 09 ii T 302 LIST OF ILLUSTRATIONS FIGURE NUMBER Page Figure 1 1 A C Component Identification 1 1 Figure 1 2 Unit Assembly Back n 1 4 Figure 1 3 Unit Assembly Inside View Typical e 1 5 Figure 1 4 Control P aniel Typical recs eb reve EE 1 6 Figure 1 5 Relay Board 12 00371 00 1 7 Figure 1 6 Relay Board 12 00371 01 1 8 Figure 1 7 LogicBoard Leere gae Rep ai Ms CER RE RE s 1 9 Figure 1 8 Micromate Control Panel Driver 1 9 Figure 1 9 Micromate Control Panel Full Function 1 10 Figure 1 10 Refrigerant Flow Diagram 1 13 Figure 2 1 Capacity Control Diagram
89. lay operational status for the evaporator fans while Figure 2 1 provides Logic Board speed selections at various deviations from set point 2 3 8 Fan Motor Operation Sequence The evaporator and condenser fans are energized by relays on the relay board Depending on relay board configuration the fan ON and fan HIGH SPEED relays may be directly energized by the microprocessor or they may be energized by a set of interim relays 2 3 8 1 Relay Board 12 00371 00 On systems with relay board 12 00371 00 see Figure 1 5 Power is available from relay board terminal P8 2 see Figure 5 2 to the fan ON relays K1 6 K7 and fan HIGH SPEED relays K2 amp K8 from relay board terminal J P 2 18 to the interim relays K21 K22 K23 amp K24 and from terminal board PTB1 to the fan circuit breakers CB2 CB3 CB4 amp CB5 When condenser fan operation is required the microprocessor energizes grounds relay K24 which closes a set of contacts to energize the condenser fan ON relay K7 Relay K7 closes it s contacts to energize condenser fan relays CFR 1 amp 2 Withthe CFR rela contacts closed power flows from CB4 amp CB5 throug the relay contacts to the condenser fan motors The circuit continues through a resistor R 1 for permanent magnet motors or through the motor low speed circuit A2 to 52 for wound field motors When high speed condenser fan operation is required the microprocessor energizes grounds relay K23 which
90. lve Compressor R 22 SYSTEM Figure 1 10 Refrigerant Flow Diagram 1 13 LEGEND DISCHARGE LIQUID SUCTION COOLANT T 302 SECTION 2 OPERATION 2 1 STARTING STOPPING AND OPERATING INSTRUCTIONS 2 1 1 Powerto Logic Board Before starting electrical power must be available from the bus power supply The system components receive power from two sources a 24 vac powa for the microprocessor electronics is supplied through the bus interface 24 vdc 150 amp power from a fuse the battery compartmentsupplies power forthe clutch compres sor unloader solenoids evaporator and condenser assemblies this power is controlled by the Logic Board 2 1 2 Starting O If the engine is not running start the engine OEM SUPPLIED SWITCHES Actual start sequence depends on the operating con trols supplied If only an ON OFF switch is supplied place the switch in the ON position to startthe system in the automatic mode If additional OEM switches are supplied refer to the following Micromate control description for operating instructions MICROMATE CONTROL PANEL Driver Controller The system will be started in the automatic mode The Micromate Control Panel Figure 1 8 may be programmed to display the set point temperature or return air temperature To determine which display tempera
91. minal P2 18 to the fan ON relays 1 amp K7 and fan HIGH SPEED relays K2 amp K8 and grounded thru terminals J P2 2 3 4 5 When condenser fan operation is required the microprocessor energizes grounds thru 2 5 the condenser fan ON relay K7 Relay K7 closes it s contacts to energize the condenser fan relays CFR1 and CFR2 With the CFR relay contacts closed power flows from CB4 amp CB5 through the relay contacts to the condenser fan motors The circuit continues through a resistor R 1 for permanent magnet motors or through the motor low speed circuit A2 to 52 for wound field motors or low speed circuit red to black for the brushless motors When high speed condenser fan operation is required the microprocessor energizes grounds thru J P 2 4 the HIGH SPEED relay K8 Relay K8 closes it s contacts to energize the condenserspeed relay CSR With the CSR relay contacts closed power flows directly to ground from the permanent magnet motors or through the motor High speed speed circuit A2 to S3 for wound field motors Forthe brushless motors power also flows from CB7 through a second set of K7 relay contacts to energize the motor high speed circuits orange and black white When evaporator fan operation is required the microprocessor energizes grounds thru P2 3 the relay K1 Relay K1 closes it s contacts to energize evaporator fan relays EFR1 amp EFR2 With permanent magnet motors a circuit is establi
92. n Motor Operation Sequence 2 4 Filter Drier 1 13 4 7 Filter Drier Inlet Valve 1 13 Fresh Air Connection 1 5 Fuse 1 11 H Heating Cycle 1 12 Heating Mode 2 3 High Pressure Switch 1 10 1 11 4 7 Hour Meter 2 5 L Liquid Line Solenoid 1 13 2 5 4 8 Liquid S uction Heat Exchanger 1 13 Logic Board 1 9 2 1 3 1 4 17 Low Pressure Switch 1 10 1 11 4 7 M Maintenance Schedule 4 1 Manifold Gauge Set 4 2 Micrormate Control Panel 2 1 3 1 Modes Of Operation 2 2 Noncondensibles Check For 4 6 O Oil Level Check Compressor 4 11 Operating Controls 1 5 Operating Instructions 2 1 Pre Trip Inspection 2 2 Pressure Transducer 1 11 4 13 Pump Down 4 3 4 4 Index 1 T 302 R Refrigerant Charge 1 10 4 3 4 5 4 6 Refrigerant Removal 4 4 4 5 Refrigeration Cycle 1 12 Relay Board 1 8 Relay Board 12 00371 00 1 7 5 Self Diagnostics 3 1 Service Valves 4 1 Shaft Seal Reservoir 4 10 Suction Pressure 2 3 Superheat 4 9 System Parameters 2 6 System Shutdown 2 2 System Start up 2 1 T 302 INDEX Temperature Control 2 3 Temperature Pressure Chart 4 18 4 19 Temperature Sensor 1 11 4 12 4 13 4 14 4 15 4 16 Thermostatic Expansion Valve 1 10 1 13 4 8 Troubleshooting 3 1 U Unit Assembly 1 1 Unloader Control 2 3 V Vent Mode 2 3 W Water Temperature S witch 1 10 Wiring S chematics 5 1 Index 2 12 09 Carrier Carrier Tran
93. nd an ambient temperature sensor The discharge check valve is a spring loaded normally closed valve thatopens with the flow of refrigerant from the compressor When the compressor clutch is disengaged the discharge check valve will close 12 09 1 1 preventing the flow of high pressure liquid from the condenser back into the compressor The condenser coil provides heat transfer surface for condensing refrigerant gas at a high temperature and pressure into a liquid at high temperature and pressure The condenser fans circulate ambient air across the outside of the condenser tubes at a temperature lower than refrigerant circulating inside the tubes this results in condensation of the refrigerant into a liquid The receiver collects and stores liquid refrigerant The receiver is fitted with upper liquid level sight glass to enable determination of refrigerant liquid level and a lower moisture indicator to determine refrigerant moisture content The receiver is also fitted with a fusible plug which protects the system from unsafe high pressure conditions The liquid suction heat exchanger further cools the liquid refrigerant to improve overall system efficiency The filter drier removes moisture and debris from the liquid refrigerant before it enters the thermostatic expansion valve The liquid line solenoid valve closes when the system is shut down to prevent flooding of coils with liquid refrigerant The service valves enable isolat
94. nd discharge servicing charging ports mounted on the service valves enable connection of charging hoses for servicing of the compressor as well as other parts of the refrigerant circuit The high pressure switch contacts open on a rise to shut down the system when abnormally igh refrigerant pressures occur The electric unloaders provide a means of controlling compressor capacity which enables control of temperature inside the bus 1 2 5 Fresh Air Connection A connection see Figure 1 1 is provided on the unit ne side for connection of the OEM supplied fresh air ucting 1 2 6 System Operating Controls And Compo nents The system is operated by a Carrier Transicold Micromax microprocessor controller Figure 1 4 which consists of a logic board relay board circuit breakers relays and an OEM supplied driver control panel or a Carrier Micromate control panel Figure 1 9 The logic board regulates the operational cycles of the system by 12 09 1 5 energizing or de energizing relays in response to deviations in interior temperature Modes of operation include Cooling Heatand Vent With the Micromate set in the AUTO mode the logic board will cycle the system between the operating modes as required to maintain desired set point temperature In the vent mode the evaporator fans are operated to circulate air in the bus interior In the heat mode the heat valve and the OEM supplied floor blower and or boost pump are ene
95. nect switch in OFF posi tion and lock Disconnect the wire leads to the junction box of the motor Mark the leads for proper reassembly Remove motor mounting bolts referto Figure 4 17 to the bottom channel Remove the venturi retaining clip mounting bolts securing the venturi ring Slide the blower assembly with the venturi ring out of the blower housing Loosen the two blower hub set screws to remove blower To reassemble apply an anti seize compound to the motor shaft and reverse the above procedure Position blower 1 1 16 inch from inside blower edge to venturi ring See Figure 4 17 4 19 2 Routine Examination and Cleaning a At regular maintenance periods remove brush covers and clean and examine motor interior Remove allforeign material such as dirtand carbon dust Clean by vacuum if possible to avoid blowing foreign matter into the motor Confirm free moving brushes to prevent binding Examine brush wear and general condition If brushes are broken cracked severely chipped or worn to 1 3 the length of a new brush replace them Refer to section 4 19 3 Examine the condition of the brush springs A discolored spring is a sign of overheating which may weaken the spring in which case the spring should be replaced Observe the condition of the commutator and the armature coils that are visible 4 19 3 Brush Replacement If brushes are broken cracked severely chipped or worn to 1 3 their original
96. nnect the other side of the gauge set Removing the Manifold Gauge Set O 1 While the compressor is still ON backseat the high side service valve 2 Midseat both hand valves on the manifold gauge set and allow the pressure in the manifold gauge set to be drawn down to low side pressure This returns any liquid that may be in the high side hose to the system AX CAUTION To prevent trapping liquid refrigerant in the manifold gauge setbe sure setis broughtto suction pressure before disconnecting Backseat the low side service valve Backseat both field service couplers and frontseat both manifold set nand valves Remove the couplers from the access valves Install both service valve stem caps and access valve caps finger tight only 12 09 4 3 4 4 PUMPING THE SYSTEM DOWN OR REMOV ING THE REFRIGERANT CHARGE NOTE To avoid damage to the earth s ozone layer use arefrigerantrecovery system whenever remov ing refrigerant 4 4 1 System Pump Down For Low Side Repair To service or replace the filter drier thermostatic expansion valve suction line liquid line solenoid valve or evaporator coil pump the refrigerant to the condenser and receiver as follows a Install manifold gauge set to the filter drier inlet ser vice valve Refer to Figure 4 4 Frontseatthe filter drier inlet service valve by turning clockwise Disconnect suction pressure transducer installa jumper on the compressor mounted low pres sur
97. ns b Temperature Sensors Input Range 52 6 to 158 F 47 to 70 C Output NTC 10K ohms at 77 F 25 C See Table 4 1 for calculations 1 11 ELECTRICAL SPECIFICATIONS EVAPORATOR MOTORS MOTOR TYPE WOUND FIELD PERMANENT MAGNET BRUSHLESS refer to Table 1 1 Voltage 27 27 24 28 VDC 24 28 VDC Horsepower kW 0 ag 5 0 6 0 37 0 75 0 56 0 75 0 56 Full Load Amps 5202 Speed 1800 1400 H RPM Factory Lubricated Bearing Lubrication additional grease not required 1800 Factory Lubricated additional grease not required 1800 Factory Lubricated additional grease not required or permanent magnet with resistor applications Resistor 420 watts 1 12 SAFETY DEVICES System components are protected from damage caused by unsafe operating conditions with safety devices Carrier Transicold supplied safety devices include a high pressure switch HPS low pressure switch LPS circuit breakers and fuses a Pressure Switches High Pressure Switch HPS During the A C mode compressor operation will automatically stop if the HPS switch opens due to an unsafe operating condition Opening HPS de energizes through the controller the compressor clutch shutting down the compressor The high pressure switch is installed in the center head of the compressor Low Pressure Switch LPS The low pressure switch is installed in the compressor and opens ona pressure drop t
98. ns Loose mounting hardware Defective bearings Blade interference Blade missing or broken 3 3 5 Control System Malfunction Will not control Sensor or transducer defective Relay s defective Microprocessor controller malfunction Logic Board connector unplugged 3 3 6 No Evaporator Air Flow Or Restricted Air Flow Air flow through coil blocked a eee over rty coil Di filter No or partial evaporator air flow Motor s defective Motor brushes defective E vaporator fan loose or defective Fan damaged Return air filter dirty Icing of coil Fan relay s defective Safety device open Fan rotation incorrect 3 3 7 Expansion Valve Malfunction Low suction pressure with high superheat Side to side temperature differ ence Warm Coil Low refrigerant charge Wax oil or dirt plugging valve orifice Ice formation at valve seat Power assembly failure Loss of bulb charge Broken capillary tube Wax oil or dirt plugging valve orifice Ice formation at valve seat Power assembly failure Loss of bulb charge Broken capillary 3 3 8 Heating Malfunction Insufficient heating No Heating Dirty or plugged heater core Reheat coolant solenoid valve s malfunctioning or plugged Low coolant level Strainer s plugged Hand valve s closed Water pumps defective Auxiliary Heater malfunctioning Reheat coolant solenoid valve s malfunctioning or plugged Controller malfunction Pump s malfunctioning Sa
99. o shut down the system when a low pressure condition occurs In addition if the control monitors a pressure less than 10 psig R 134a 30 Psig R 22 by the suction pressure transducer 12 09 mounted in the evaporator section the system will be shut down for at least one minute b Fuses and Circuit Breakers The Relay Board is protected against high current by an OEM supplied 150 amp fuse or circuit breaker Independent 60 amp circuit breakers protect each motor while the output circuits are protected by additional 15 amp circuit breakers During a high current condition the breaker or OEM fuse may open When power is removed from a device a breaker alarm will be generated c Ambient Lockout The ambient temperature sensor located in the condenser section measures the condenser inlet air temperature When the temperature is below the cutout set point the compressor is locked out until the temperature rises above the cut in setting The set points will be programmed to cutout at45 F 7 2 C and cut in at 50 F This setting protects the compressor from damage caused by operation at low temperatures T 302 1 13 AIR CONDITIONING REFRIGERATION CYCLE When air conditioning cooling is selected by the controller the unit operates as a vapor compression system using R 22 or R 134a as the refrigerant see Figure 1 10 The compressor raises the pressure and the temperature of the refrigerant and forces it thru the
100. o transmit engine power to the air conditioning compressor De energizing the clutch electric coil disengages the clutch and removes power from the compressor The clutch will be engaged when in cooling and disengaged when the system is off in heating or during high and low pressure conditions The clutch coil will be de energized if the discharge pressure rises to the cutout setting of the compressor mounted high pressure switch An alarm will be triggered if this condition exists for more than a 0 5 second The clutch coil will energize when the discharge falls to the reset point of the high pressure switch The clutch coil will be de energized whenever the suction pressure decreases below 6 PSIG An alarm will be rigged if this condition exists for more than 10 seconds The clutch coil will energize when the suction pressure rises to the reset point If the alarm is triggered 3 times in a 30 minute time period the system will be locked out See 3 2 1 Alarm Codes The clutch is prevented from engagement when the ambient temperature is below ambient lockout setpoint 2 3 11 Liquid Line Solenoid Control The liquid line solenoid is energized open when the compressor clutch is energized and de energized closed when the clutch is not 2 3 12 Alarm Description Alarm descriptions and troubleshooting procedures are provided in section 3 2 3 13 Hour Meters Hour meter readings are available in the parameter code li
101. ode With the system in normal operation the controller may be placed in the test mode by doing the following a Enter the diagnostic mode by pressing the UP and DOWN arrow keys simultaneously for 3 seconds En ter the test mode immediately by pressing the COOL button five times In the test mode the display will read where indicated the test number that is currently run ning The initial indication will be This indicates the controller is in the test mode and all relays are de en ergized Press the DOWN arrow key to bring the Mi cromate to the next test screen and energize the cor responding component s Press the UP arrow key move backwards through the list A listing of tests is provided in Table 2 3 To terminate testing press the I 0 key O T 302 2 6 Table 2 3 Controller Test List T00 01 2 T03 Evaporator Fans High On Evaporator Fans Low On Condenser Fans High Om CondenserFansLow T05 Compressor amp Liquid Line Solenoid T06 Unloader Valve 1 Unioader Valve On T08 T09 T10 T11 Not Applicable Om Reheat Coolant Vave On Faw _________ Boost Om T12 S pare Motor Input Floor Blower 12 09 Table 2 4 Parameter Codes CODE CODE NAME DESCRIPTION P1 Return Air This value is the temperature measured by the return air sensor If the sensor Temperature is shorted
102. ompressor service valves and disconnect manifold gauge set Check refrigerant level Refer to paragraph 4 7 1 It may be necessary to clear any alarms that have been generated 12 09 5 Thermistor Vacuum Gauge 6 Vacuum Pump 7 Reclaimer 8 Refrigerant Cylinder Filter Drier Filter Drier Inlet Service Valve Manifold Gauge Set Suction Service Valve and Port Figure 4 6 System Charge Removal Connections 4 4 4 Removing Entire System Charge To remove the entire refrigerant charge do the following a Connect a manifold gauge set to the system as shown in Figure 4 6 b Connecta reclaimer to the center manifold gauge set connection c Recover refrigerant in accordance with reclaimer manufacturers instructions 4 5 REFRIGERANT LEAK CHECK A refrigerant leak check should always be performed after the system has been opened to replace or repaira component To check for leaks in the refrigeration system perform the following procedure NOTE It must be emphasized that only the correct re frigerant should be used to pressurize the sys tem Use of any other refrigerant will contami nate the system and require additional evacuation a Ensure the service valves are open and power the liq uid line service valve from an external source If system is without refrigerant charge system with refrigerant vaporto build up pressure to approximate ly 30 PSIG R 134a or 45 PSIG R 22 Add su
103. ove refrigerant using a refrigerant recovery sys tem Evacuate and dehydrate the system Refer to para graph 4 6 Charge the unit Refer to paragraph 4 7 2 12 09 4 9 CHECKING AND REPLACING HIGH OR LOW PRESSURE SWITCH WARNING Do not use a nitrogen cylinder without a pressure regulator WARNING Do not use oxygen in or near refrigeration system as an explosion may occur a Disconnect wiring and remove switch from unit All units are equipped with a schrader valve at the pres sure switch connections Connect switch to a cylinder of dry nitrogen See Figure 4 7 Cylinder Valve and Gauge Pressure Regulator Nitrogen Cylinder Pressure Gauge 0 to 400 psig 0 to 27 22 bar Bleed Off Valve 1 4 inch Connection Figure 4 7 Checking High Pressure Switch Connect an ohmmeter across switch terminals Setnitrogen pressure regulator higher than the upper switch setting refer to paragraph 1 8 For a high pressure switch close cylinder valve and open bleed off valve Open cylinder valve and slowly close bleed off valve The switch should open no continuity with in required cut out tolerance Close cylinder valve and release pressure through the bleed off valve As pressure drops switch should close continuity within required cut in tolerance For a low pressure switch close cylinder valve and bleed off valve Open cylinder valve to bring pres sure above the cutout settin
104. permanent Magnet TTE 35 604 82 R 134A YES Cleanable 68RM35 604 83 R 134A YES Wound Field Wound Field Cleanable R R Cleanable Cleanable Cleanable Cleanabie 68RM35 604 88 R 134A YES Permanent Magnet Permanent Magnet Cleanable Cleanabie Cleanable 68RM35 604 94 R 134A YES P Permanent Magnet Disposable 68RM35 604 95 R 134A YES Permanent Magnet Permanent Magnet Cleanable 68RM35 604 96 R 134A YES Disposable Table 1 2 Additional Support Manuals MANUAL FORM NUMBER EQUIPMENT COVERED TYPE OF MANUAL T 302PL 68RM 35 104 604 Units Service Parts List 62 02756 056 Compressor Workshop Manual T 200PL 056 Compressor Parts List 62 11052 056 Twin P ort Compressor Workshop Manual 62 11053 056 Twin P ort Compressor Parts List 12 09 1 3 T 302 ROADSIDE RS bo TIEN 0 Condenser Fan Motor 1 Filter Drier Outlet Valve Filter Drier Ambient Temperature Sensor Filter Drier Inlet Valve Condenser Fan Motor CM2 Receiver Fusible Plug Condenser Coil Discharge Line Check Valve Discharge Line Isolation Valve Sight Glass SD 9 CURBSIDE CS Number Plate 4 D 19 18 Moisture Liquid Indicator Discharge Pressure Transducer Evaporator Fan Housing Curbside Discharge Line Connection Suction Line Connection Suction Pressure Transducer Evaporator Fan Motor EFM2 Liquid S uction Heat Exchang
105. rgized The evaporator fans operate to circulate air over the evaporator coil in the same manner as the vent mode In the cooling mode the compressor is energized while the evaporator and condenser fans are operated to provide refrigeration as required The compressor is fitted with cylinder unloaders to match compressor capacity to the bus requirements Once interior temperature reaches the desired set point the system may operate in the clutch cycle or reheat mode A controller programmed for clutch cycle will de energize the compressor clutch and allow the system to operate in the vent mode until further cooling is required A controller programmed for reheat will maintain compressor operation and open the heat valve to allow reheating of the return air In the reheat mode interior temperature is maintained atthe desired set point while additional dehumidification takes place T 302 Wound Field Typical 3 4 5 6 7 8 9 10 je e 5459 KE 414 a DE 0 0 CSR a SJ m gt 9 m gt ES
106. shed from circuit breaker CB3to the motors in series placing them in low speed For wound field motors the circuit is established throu ugh the motor low speed circuits A2 to S2 or low speed circuit red to black for the brushless motors When high speed evaporator fan operation is required the microprocessor energizes grounds thru J P 2 2 the evaporator fan HIGH SPEED relay K2 Relay K2 closes its contacts to energize the evaporator speed relay ESR With permanent magnet motors the ESR contacts reverse allowing power from CB2 directly to EM2 and power from CB3 to EM1 placing them in high speed For wound field motors the circuit continues through the motor high speed circuit A2 to S3 For the brushless motors power also flows from CB7 through a second set of K1 relay contacts to energize the motor high speed circuits orange and black white 12 09 2 3 9 Condenser Fan Control The condenser fans are energized when the compressor clutch output is energized The fans are started in low speed and will remain in low speed until the discharge pressure increases to 190 psig R 134a or 360 psig R 22 The fans will remain in high until discharge pressure decreases below 135 psig R 134a or 285 psig R 22 The fans will also be activated if a high pressure alarm has been activated has not been locked out refer to Table 2 3 10 Compressor Clutch Control A belt driven electric clutch is employed t
107. sicold depending on the application The controller automatically controls the reheat coolant valve and boost pump during the heating and reheat modes to maintain required temperatures inside the bus Engine coolant glycol solution is circulated through the heating circuit by the engine water pump When the reheat coolant valve solenoid is energized the valve will open to allow engine coolant to flow through the heater coil The valve is normally closed so that if a failure occurs the system will be able to cool 12 09 12 09 i 1 2 3 4 5 6 7 8 9 25 26 Expansion Valve Expansion Valve Equalizer Line Liquid Line Solenoid Valve Expansion Valve Bulb Filter Drier Inlet Service Valve Filter Drier Outlet Service Valve Auxiliary Cooler Liquid Connection S ubcooler Condenser Coil Filter Drier Liquid S uction Heat E xchanger Discharge Check Valve Refrigerant Sight Glass Fusible Plug R 134a SYSTEM Charge Isolation Valve Moisture Indicator Receiver Service Port High Side Pressure Transducer High Side High Pressure S witch Low Pressure Switch Auxiliary Cooler Suction Connection Service Port Low Side Pressure Transducer Low Side E vaporator Coil Heater Coil Reheat Coolant Va
108. sor be low 500 microns Evacuate and dehydrate only after pressure leak test Refer to paragraph 4 5 Essential tools to properly evacuate and dehydrate any system include a good vacuum pump with a mini mum of 6 cfm 10 2 m3 hr volume displacement CTD P N 07 00176 11 and a good vacuum indica tor CTD P N 07 00414 00 c Keep the ambient temperature above 60 F 15 6 C to speed evaporation of moisture If ambient temper ature is lower than 60 F 15 6 C ice may form be fore moisture removal is complete 4 6 3 Procedure for Evacuation and Dehydrating System Triple Evacuation Remove refrigerant using a refrigerant recovery sys tem Refer to paragraph 4 4 4 The recommended method is connectin OD copper tubing or refrigerant hoses vacuum service as shown in Figure 4 6 c Make sure vacuum pump valve is open Start vacuum pump Slowly open valves halfway and then open vacuum gauge valve Evacuate unit until vacuum gauge indicates 2000 mi crons Hg vacuum Close gauge valve vacuum pump valve and stop vacuum pump f Break the vacuum with dry nitrogen Raise system pressure to approximately 2 psig Purge the nitrogen from the system Repeat steps d thru g one time i Start vacuum pump and open all valves Dehydrate unit to 500 microns Hg vacuum a b lines 3 8 esigned for T302 Close off pump valve and stop pump Wait five min utes to see if vacuum holds
109. sport Air Conditioning RGC United Technologies Company York PA 17406 USA Carrier Transicold Division Tel 1 800 673 2431 Carrier Corporation Fax 1 717 764 0401 Transport Air Conditioning Group P O Box 4805 Syracuse 13221 U S www carrier transicold com A member of the United Technologies Corporation family Stock symbol UTX TRANSICOLD 2009 Carrier Corporation D Printed 0 S 1209
110. st of the Micromate The hour meters record the compressor run time and the total time the evaporator fans are on The maximum hours are 999 999 R efer to paragraph 2 4 2 for instructions on reading parameter codes 2 4 MICROPROCESSOR DIAGNOSTICS The Micromate allows the user to interface with the microprocessor based control This allows system parameters alarms and settings to be viewed and modified 12 09 2 5 2 4 1 Control NOTE 1 This procedure should be performed by an HVAC technician who has been trained on Carrier Model RM system design The control configuration is preset by the manufacturer and resetting of the parameters should not be required It is recommended that Carrier Service or Engineering is contacted before any control configuration is changed Carrier can not be responsible for failures or damage resulting from unauthorized changes 2 IfareplacementLogic Module is installed it is necessary to match the configuration jumpers refer to Figure 1 7 to the original board Refer to paragraph 4 21 a Turn the A C main power switch located in the driv er s area to OFF b Connect the Micromate to the service port located in the return air section refer to Figure 1 4 23 c Unplug the logic board connector J3 refer to Figure 1 7 d Turn the A C main power switch back to the ON posi tion e Activate the system by pressing the I O key on the Mi cromate panel NOTE Be sure to reconnect
111. stuck closed Restricted air flow No evaporator air flow or restriction Heating system Reheat coolant valve stuck open 3 3 3 Abnormal Pressures High discharge pressure Discharge transducer failure Refrigerant overcharge 7 1 Noncondensable in system 2 Condenser motor failure Check Condenser coil dirty Clean Low discharge pressure Discharge transducer failure See Note Compressor valve s worn or broken See 1 2 Low refrigerant E High suction pressure Compressor valve s worn or broken See 1 2 Low suction pressure Suction service valve partially closed Filter drier inlet valve partially closed Chec Filter drier partially plugged 4 10 Low refrigerant charge 4 7 Expansion valve malfunction 3 3 7 Restricted air flow 3 3 6 Suction transducer failure Replace Suction and discharge pressures Compressor valve defective See Table 1 2 tend to equalize when system is operating 3 3 4 Abnormal Noise Or Vibrations Compressor Loose mounting hardware Check Tighten Worn bearings See Table 1 2 Worn or broken valves SeeTable 1 2 Liquid slugging 3 3 7 Insufficient oil 4 14 4 Clutch loose rubbing or is defective Check V belt cracked worn or loose Check Adjust Dirt or debris on fan blades Clean T 302 3 4 12 09 Table 3 3 General System Troubleshooting Procedures Continued INDICATION REFERENCE TROUBLE POSSIBLE CAUSES SECTION 3 3 4 Abnormal Noise Or Vibrations Continued Condenser or evaporator fa
112. sultant pressure will forcibly discharge compres sor oil 2 Drain or pump out compressor oil until the level is brought to or just below the 1 2 sightglass maximun 3 Evacuate the compressor to 500 microns Backseat the compressor service valves and repeatthe oil lev el check procedure f To add oil to the compressor do the following 1 With the system off connecta manifold gauge setto the compressor suction and discharge service valves Front seat both service valves to isolate the compressor from the system See Figure 4 5 and reclaim the refrigerant to below atmospheric pres sure Shut off the reclaimer and verify the pressure does notrise If the pressure rises continue reclaim ing until the pressure remains below atmospheric 2 Add oil to compressor crankcase slowly through the oil fill plug opening see Figure 4 12 to bring level to mid range of allowed levels 3 Evacuate compressor to 500 microns Backseat compressor suction and discharge valves start sys tem and recheck oil level 4 Remove manifold gauge set 4 14 5 Checking Unloader Operation To check unloader operation do the following a Install a manifold gauge set as shown in Figure 4 6 Ensure both manifold valves are frontseated and cen ter connection is tight on blank fitting Midseat compressor suction service valve Disconnect the suction pressure transducer Figure 1 10 24 This will force the controller to ener gize the unload
113. t p 5 2 AVIS ADT C vaga 91507 8814 quo 1 8 3SIN d 35010 79 4 390 Ka Kolo v 541 AWTS L3H gt gt lt MOI lt 58 98 2AN Wei aJ VOL 01700 d BI d 35019 58 98 3514 9 390 TAN K Ko ToD var 58 98 ANTE 8 98 CAVIaSI0 d V 7 3LNWOSIQIN OT SND T 302 68RM35 104 40 ircui 5 3 Figure 5 2 Wiring Schematic Control C 12 09 5 a 2 ALTERNATOR A C FAIL DRIVER CONTROL MODULED GLO e 1 11 65 N PIB 98 62125 Figure 5 3 Wiring Schematic Power Circuit 68RM35 104 40 302 5 4 12 09 01700 9050 39 35075 3SIN d avoa 21901 E 5 zd 3 B B 1 r L 1 5 S se 3SI d 35019 6 9 31 4 lt 3500
114. t FAIL SIGNAL Go Pe BOOST PUMP 98 62469 Figure 5 37 Wiring Schematic Power Circuit 68RM35 604 63 70 79 86 T 302 5 38 12 09 199 01 3409 4 davoda 21907 a mese 3 wos HOIH ay an Cald 3500 1601 9 lt Do aba 3 14 4 35012 s 629 4030 49 340 16 1 oiu 017002 4094 35072 OTFOOE 3SIN d 390 224 1 5 O HOIH 3 5 39 T 302 Figure 5 38 Wiring Schematic Control Circuit 68RM35 604 66 82 12 09 gt 9 Bev ALTERNATOR EFR1 CB7 154 ACSL 4 AC FAIL SIGNAL BOOST PUMP 98 62505 Figure 5 39 Wiring Schematic Power Circuit 68RM35 604 66 82 T 302 5 40 12 09 aaao NDIIVMOSIJNDO N3dWnr 5908 21907 va av 5 9v 484 15008 O 20 90 er O s B Ei Bl sr 2908 21901 6 62 3SIN d 35019 79 dDNI d 390 Figure 5 40 Wiring Schematic 68RM35 604 67 83 T 302 5 41 12 09 98 03232 ald 49 gt 3 151 I 199 913 0 W3dWnr 21901 d b b 2 s ANTH ADT 3 ANOO ANTH H9IH 3 CONDO
115. t have been generated T 302 4 4 1 Discharge Service Valve and Port 2 Suction Service Valve and Port 3 Manifold Gauge Set 4 Vacuum Pump 5 Reclaimer 6 Refrigerant Cylinder 7 Thermistor Vacuum Gauge Figure 4 5 Compressor Service Connections 4 4 3 Pump Down An Operable Compressor For To service an operable compressor Repair pump the refrigerant into the condenser coil and receiver as follows a b O Install manifold gauge set Refer to Figure 4 5 Frontseat the compressor suction service valve by turning clockwise Install a jumper on the compressor mounted low pres sure Switch Start the unit and run in cooling until 10 25 4 cm hg of vacuum is reached Shut sys tem down and tag out system power source Frontseat the compressor discharge service valve and wait 5 minutes to verify that vacuum is main tained If the pressure rises above vacuum open the compressor discharge service valve and repeatsteps c and d until a vacuum is maintained Service or replace components as required and leak check the compressor Using refrigerant hoses designed for vacuum service connect a vacuum pump to the center connection of the manifold gauge set Evacuate system to 500 mi crons Close off pump valve isolate vacuum gauge and top pump Wait 5 minutes to verify that vacuum olds Once vacuum is maintained re connect low pres sure switch Backseat c
116. the system in the reheat mode to keep the compres sor fully loaded throughout this procedure Ensure the system is fully charged refer to paragraph 4 7 1 and the compressor crankcase is warm to the touch after fifteen minutes of operation c Shut off the system and immediately record the oil level in the compressor si ae See Figure 4 12 If the compressor is not level an average between the sight glass levels will have to be made to deter mine level d The correct oil level for this application should be be tween the bottom and 1 2 of the oil level sightglass See Figure 4 12 If the oil level is correct release the coach into service If the level is above the 1 2 sight 01855 maximum to step e levelis ow the 1 2 sightglass maximum proceed to step f To remove oil and bring the level to the 1 2 sightglass maximum do the following 1 With the system off connecta manifold gauge to the compressor suction and discharge service valves Front seat the service valves to isolate the compressor from the system See Figure 4 5 and T 302 4 12 reclaim the refrigerant to below atmospheric pres sure Shut off the reclaimer and verify the pressure does notrise If the pressure rises continue reclaim ing until the pressure remains below atmospheric WARNING Extreme care must be taken to ensure that all the refrigerant has been removed from the compressor crankcase or the re
117. tion is removed the unit will default to high speed in reheat mode and in the low speed cool band If not removed heat reheat will default to low speed High Vent When this configuration is removed the unit will default to high speed in vent mode If not removed vent mode will default to low speed Heat When this configuration is removed the unit will run on 100 reheat instead of eat Reheat Cycle When the reheat cycle configuration is removed the unit is in reheat mode The default configuration is cycle clutch mode Transducers When the transducer configuration is removed transducers will assume to be present Unit Type Rearmount unit enabled with G removed and H installed Unit Type With removed and installed roof top unit will be enabled Factory Reserved for the manufacturer Invert H20 When this configuration is removed the logic for the water temperature switch will be inverted rA When this configuration is removed the voltage selection will be changed from 12 to 24 vdc Factory Reserved for the manufacturer A C G Psig Bars When this configuration is removed the display will indicate pressures in bars When not removed the display will indicate pressures in psig Refrigerant R 22 R 134a When the refrigerant configuration is removed the refrigerant is set for R 22 The default refrigerant is 134a E F K L N C F W
118. torque After the delay unloaders may be de energized Any subsequent changes between energizing and de energizing the unloaders for temperature control is also staged for a preset delay time Once an unloader is energized for pressure control it remains energized for two minutes to prevent short cycling Only one unloader may change state ata time when staging is required Operating parameters for temperature control suction pressure control and discharge pressure control are as follows a Temperature Control The unloaders are used to control system capacity by controlling compressor capacity 1 Compressor Unloader UV1 Relay When return air temperature falls to less than 2 F 1 1 C above set point unloader UV1 is energized If temperature rises to ea than 3 F 1 7 C above set point UV 1 will be de energized to place the compressor at 100 capacity 2 Compressor Unloader UV2 Relay When return air temperature falls to less than 1 F 0 6 C above set point unloader UV2 is energized If temperature rises to than 2 F 1 190 above set point UV 2 will be de energized to place the compressor at 66 capacity b Suction Pressure The unloaders are used to control suction pressure and thereby prevent coil frosting 1 Compressor Unloader UV1 Relay When the suction pressure decreases below 26 psig R 134a or 50 psig 22 unloader UV 1 is energized unloading cylinder bank two cylinders this output
119. ture is programmed press the TEMPERA TURE button so thatthe OUT SIDE AIR indicator is illuminated If the controller cycles back to the IN SIDE AIR indicator then the controller is pro grammed to display return air temperature If the controller does not automatically cycle back to the return air indicator then the controller is pro grammed to display set point temperature startthe system press the 1 0 button to illuminate the indicator light and signal the Logic Board to per form start up After the pre trip inspection is com pleted the switches may be set in accordance with the desired control modes To read interior or exterior temperature press the TEMPERATURE button to illuminate the indicator light and bring the display to the desired temperature reading After a short delay the display will return to the default set point or return air temperature read ing Setpoint may be changed by pressing the UP or DOWN arrow button The UP button will increase the setpoint temperature and the DOWN button will de crease the setpoint temperature MICROMATE CONTROL PANEL Full Function Controller 12 09 2 1 It the system be started in the automatic mode 5 The Micromate Control Panel see Figure 1 9 may be programmed to display the set point temperature or return air temperature To determine which dis play temperature is programmed press the PERATURE button so thatthe OUT SIDE AI
120. ure Communication F ailure Failure in communication between the logic board and MDST and mulge are Program Memory Display program memory failure 3 2 SYSTEM ALARMS 3 2 2 Activation 3 2 1 Alarm Codes When alarms are detected they are placed in an alarm The Micromax Logic Board continuously monitors queue in the order at which they initiated unless the system parameters and will generate an ALARM if a alarm is already present Each alarm recorded will also parameter exceeds preset limits Alarms are indicated capture evaporator hour meter reading and the controller will respond in accordance with the corresponding to the activation time If the AUTO key is information provided in Table 3 2 The alarm codes can pressed while an alarm is displayed the activation time be read by counting the number of times that the Logic capture will be shown Board CODE LED see Figure 1 7 flashes Each alarm code is a two digit number the first set of flashes is the 3 2 3 Alarm Queue first digit and after a slight pause the second set of flashes is the second digit The alarm queue consist of 10 alarm locations When the alarm queue is full the Logic Board will take the TheMicromate control paneldisplay will indicate alarms required action but the alarm will recorded When with the code 1 where 5 an active alarm this situation occurs an Alarm Queue F ull alarm will be prefix i is an inactive al
121. valve must be transferred to the replacement compressor The lug arrangement removed from the replacement is installed in the original compressor as a seal If piston is stuck it may be extracted by threading a socket head capscrew into top of piston A small Teflon seat ring at the bottom of the bypass piston plug must be removed GA KET SPRING 4 COVER CAPSCREWS NOT INTERCHANGEABLE WITH CONTROL VALVE SCREWS COMPRESSOR HEAD 2 55 PISTON PLUG Figure 4 13 Removing Bypass Piston Plug h Remove the pressure switches and install on replace mentcompressor after checking switch operation re ferto paragraph 4 9 Remove clutch assemble and retain original clutch key Install on replacement compressor Install compressor in unit by performing the removal steps in reverse It is recommended that new lock 12 09 nuts be used when replacing compressor Install new gaskets on service valves and tighten bolts uniformly 55 to 80 ft lbs suction and 20 to 30 ft lbs discharge service valves Leak check connections and replace filter drier Re fer to paragraph 4 5 1 Using refrigeranthoses designed for vacuum service connecta vacuum pump see Figure 4 5 and evacu ate compressor to 500 microns Frontseat both man ifold valves to isolate the pump m Open compressor service valves n Start unit and check refrigerant level refer to para graph 4 7 1 o Che
122. vercharge 4 7 2 Adding Full Charge O Install manifold gauge set at compressor suction service valve and filter drier inlet service valve See figure Figure 4 6 D e and dehydrate system Referto paragraph Place refrigerant cylinder on scales Pre pare to charge liquid refrigerant by connect charging hose from container to center connection on gage manifold Purge air from hoses Note weight of refrigerant and cylinder e Open cylinder valve backseat discharge valve on gauge manifold and allow liquid refrigerant to flow into the high side of the system T 302 4 6 h When correct charge has been added refer to para graph 1 8 close cylinder valve and frontseat manifold discharge valve Atthis point the high side of the sys tem has been charged but the low side is still in a vac 2 liquid line solenoid is normally closed Prepare the cylinder as required to allow vapor charg ing Backseat the manifold suction valve and charge vapor to build 30 PSIG R 134a or 60 PSIG R 22 pressure on the manifold suction gauge Close cylin der valve and frontseat suction manifold set Check charge level in accordance with the proce dures of paragraph 4 7 1 4 7 3 Adding Partial Charge a Install manifold gauge set at the compressor suction service valve and filter drier inlet service valve See figure Figure 4 6 Place appropriate refriger
123. w This is the number of degrees below setpoint before the reheat coolant valve is energized This value can be modified between 0 and 10 degrees F The default value is 2 degree F for heat and 4 degrees F for reheat Compressor Safety This number is the minimum time in minutes that the compressor must be off Off Delay after a high or low pressure alarm before it can be restarted This value can be modified between one and five minutes The default value is 1 P13 P14 Fan Delay This is the minimum time in seconds that the fans must run at a particular speed before changing to another speed This value can be modified between one and 60 seconds The default value is two seconds P15 Reheat Valve Delay This is the minimum time in seconds that the reheat valve must be in a par ticular state open closed before changing to another state This value can be modified between 1 and 60 seconds The default value is 2 seconds P16 55 ee This is the current state of the compressor high pressure switch input CL will Pressure Switc be displayed if it is closed and OP will be displayed if it is open 17 Condenser Not used Speed Switch 19 Maximum Setpoint This is the maximum value that the operator will be allowed to set the setpoint temperature The value can be modified in degrees with the up and down keys to a value between 60 F and 80 F P Minimum Setpoint This is the minimum value that the oper
124. w values are zero the alarm is disabled 27 Maintenance 2 Hours This is the value of evaporator fan hours low 23 at which maintenance alarm Low 32 will be activated This value can be modified by the up and down arrow keys If both high and low values are zero the alarm is disabled P28 Freeze Alarm Setting This is the value at which the freeze alarm will be activated The default value 32 F This value be modified between 20 F and 40 F one degree crements by using the arrow keys P29 Relay Module Voltage This is the voltage being supplied to the relay module P30 Main Board Software This is the software version of the logic board Version P31 Software This is the software version of the display module ersion Heat Set Point Offset This value is the offset that can be used to change the points at which the unit switches between heat and vent in the heat mode A positive value will raise the critical temperatures winter use and a negative value will decrease the critical temperatures Summer use Wy Wi N RB Default Display Tem This value determines what temperature value the driver s display will show as perature a default When the value is OFF set point temperature is displayed When the value is ON return air temperature is displayed This option is only avail able in logic module software revisions 1 9 and newer and drivers display soft ware rev
125. water temperature switch WTS The WTS is located on the engine block of the vehicle and is provided by the OEM It senses the engine coolant temperature and reverses its contacts on temperature rise at 105 F The switch prevents the circulation of cooler air throughout the vehicle as the engine comes up to temperature 2 3 4 Boost Pump Optional When the unitis in the heat mode and if a boost pump is supplied by the coach manufacturer the boost pump relay is energized providing 24 VDC to activate the boost pump 2 3 5 Vent Mode In the vent mode the evaporator fans are operated to circulate air in the bus interior 2 3 6 Compressor Unloader Control When operating in cooling the unloaders are used to system capacity as return air temperature approaches set point Operation of the unloaders ances system capacity with the load and thereby ele overshoot from set point Relay Board mounted unloader outputs control the capacity of the compressor by energizing or de energizing unloader solenoid valves The model 05G compressor has three banks of two cylinders each Energizing a valve de activates a bank of cylinders The outboard cylinder banks of the 05G are with unloader valves UV1 and UV2 each controlling two 12 09 2 3 cylinders this allows the 05G to be operated with two four or six cylinders Whenever the compressor is started the unloaders are energized for a preset delay time to reduce starting
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