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Bus Air Conditioning Unit - North America Transport Air Conditioning

1. PBI e RIBS O 2 CB4 ZAN 3 CBS H Ty 4 2 A20 O DR2 85 86 CBE i gt 0 220 2 5 2 A2CON Ai tel P FLOOR BLOWERS views qua mie 5 2 307 87 M ac yt EM L CB2 La 1 TX gt WP 8 1 2 30 87 C WE 24VDC 3 DEF 5 W ci d UL oi ipte 10 2 6 85 86 WSV ADI FANS 11 I TB13 P SWV 3 CATO 12 2 H 13 H L EL D E A H 3 I 14 30 87A 30 87 A ACFL2 L7 TBI 4 15 5 Uni lt WATER VALVE F 1 ZE GREEN lan 16 D5 Z Um 87 85 SI RELAY 1 RELAY eal T MC3 CMTH 2 17 lt 4 3 4 y J MC4 CMTH 18 ELECTRONIC 34 255 CONTROL 06 TB10 CFS 5 RELAY 3 c 19 Ve 1 20 Lo 21 I 22 23 30 87A 02 BI TB4 WTS gt 3 24 85 86 L B2 Y 85 86 L 22 JB 2 Energized Circuit De energized Circuit Figure 2 6 Vent ode with Clutch C yclin
2. 2 CB3 MC2 PTB2 PTBI 1002 1 2 C 1 2 DRI 0 180 Tux 1 2 XI MC3 CBS Casi MCS Tx 11 1112 1 2 w N 7 C2 112 DR2 nca AUN 0 22a vx 2 1115 1 2 4 FLOOR BLOWERS 1 2 30 87 Jl X SET CB2 W P E Ke Be d gt 1 2 30 87 c TM 24VDC 3 TBS W 30 87 EX Chr fr lt 5 85 86 WSV Z DI Nyce 4 5 gt H FPTS L L 19 ree 39 TA i ACFL2 Leen YELLOW x da pest Pe cF d d MATER VALVE 87 85 86 RELAY 1 RELAY 2 MC3 TB2 24V K 7 J a MC4 ELECTRONIC Ah CONTROL 4 3 4 GND HEAT RELAY 3 TBIO pes gt S SC 3574 RED DEN we A Log CB HE Tea Pe TB14 EBS 03 y 2 L lt Gast TE HW 1 2 30 Tea 12 TB12 sul SCH MCI a 3 4 me PT 7 85 86 BI F TB8 CY Tea 85 86 D2 Bi 4 WS o gt 3 TB 85 86 30 Dur L B2 Y 85 86 Figure 5 6 Electrical Schematic Wiring Diagram odel 68 40 504 23 Dwg No 68RM 40 1154 Sheet 2 of 2 5 13 10 11 12 13 14 15 16 17 18 19
3. 2 3 2 3 Temperature Controller Sequence Cycling Clutch 2 3 2 4 Air Conditioning M ode with Reheat Controller 2 4 2 5 Air Conditioning M ode with Clutch Cycling Controller 2 5 2 6 Vent M ode with Clutch Cycling Controller 2 6 2 7 Heat M ode with Clutch Cycling Controller 2 7 4 1 Manifold Gauge Sets c ca Hiei RI REL REIR aio 4 1 4 2 Vacuum Pump Connections 4 3 4 3 Checking High Pressure Switch 4 4 4 4 Thermostatic Expansion Valve 4 5 4 5 Removing Bypass Piston 4 6 4 6 056 Compressor cive i LEE Goa iene Da RC 4 6 4 7 Electric U nloader Schematic 4 8 5 1 Electrical Schematic Wiring Diagram M odels 68R 40 504 amp 524 5 2 5 2 Electrical Schematic Wiring Diagram Model 68R M 40 504 5 5 4 5 3 Electrical Schematic Wiring Diagram odel 68 M 40 504 3 amp 504 7 5 6 5 4 Electrical Schematic Wiring Diagram M odel 68 40 504 13 5 8 5 5 Electrical Schematic Wiring Diagram Model 68R M 40 504 27 5 10 5 6 Electrical Schema
4. 3 4 EUM J J 4 CMTH 2 ELECTRONIC 3 4 CONTROL 06 TB10 CFS RELAY 3 i gu A RED n HPS LPS L TC TB11 Y redire SUE 85 86 VENT p D3 P 812 3524 SES 4 Y 82 7814 HI lt e 0 30 87A 3 4 BI F N 6 O 30 87 85 86 02 BI WTS gt nJ 85 86 f 1 B2 a 85 86 ala E D wg No 68R M 40 1064 Sheet 2 of 2 5 7 JB 2 Figure 5 3 Electrical Schematic Wiring Diagram M odels 68R M 40 504 3 amp 504 7 20 21 22 23 24 25 LINE 30 32 33 34 12 20 10 11 2 4 6 8 24 6 7 8 9 2 4 3 5 27 29 10 32 16 13 18 26 18 20 26 25 2 30 7 23 21 8 22 9 25 26 20 17 18 21 11 14 CUSTOME 8 19 4 16 2 21 4 19 6 28 11 5 33 SYMBOL B CBI CB2 CB3 CB4 CBS CFS END DESCRIPTION BLOWER RELAYS COOL RELAY CIRCUIT BREAKER CIRCUIT BREAKER CIRCUIT BREAKER FLOOR HEATER 8 AMPS COOL amp WATER PUMP RELAY 15 AMP EVAP FAN MOTOR NO 1 35 AMPS CIRCUIT BREAKER EVAP FAN MOTOR NO 2 35 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR NO 1 50 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 AMPS CONDENSER FAN SWITCH CONDENSER FAN MOTOR DIODE EVAP BLOWER MOTOR EVAP SPEED RELAY FLOOR BLOWER RELAY FREEZE PROTECTION TEMPERATURE SWITCH
5. 17 5 CLIMATE CONTROL SWITCH 10 DEF DRIVER DEFROST SWITCH 12 SWV SIDE WATER VALVE CHEATER 8 WP WATER PUMP 11 WSV WATER SOLENOID VALVE MAIN WATER VALVE 24 WTS WATER TEMPERATURE SWITCH ENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS WIRING Figure 5 1 Electrical Schematic Wiring Diagram odels 68RM 40 504 amp 524 D wg 688 M 40 314 Rev B Sheet 1 of 2 5 2 24VDC i EE agi Mi CB3 MC2 PTBI EMT ga f f 1112 1 2 d A20 112 DRI CB4 0 18 vx eno 1 2 MC3 CBS MCS 1112 1 2 AT _ 2 1112 DR2 MC4 be ZA 0 220 2 1112 1 2 A2 C 7 F FLOOR BLOWERS 1 2 30 87 M She CSA CB2 W P Em X gt WP Sr 1 2 18 be 24VDC 3 mE T m W 30 87 D 7 9 5 85 86 WSV Z DI owe 4 TB13 P d NN H D me p D E A G gt 1 I 202480 ACFL2 aen YELLOW E WATER VALVE 30 87 85 86 1 2 MC3 CMTH TB2 24V K 2 3024 E s CMTH ELECTRONIC
6. 2 7 2 87A MC3 CBS A2 51 pits 1 2 N 932 MC2 MC4 CBE Al 51 Eed 2 5 1112 1 2 cm2 534 2 MC5 CA F i FLOOR BLOWERS 1 2 30 8 M FRAN T ER CB2 W P Si Bed gt WPF 1 2 30 87 ii C P CC 16 87 30 85 86 DEF 5 W pe 2 o lt 85 86 Z DI TB13 P SUV gt Leesch h H FPTS A A Se D E A C gt T pO CBTA ACFL2 TB YELLOW N rie L F 1 d WATER VALVE 87 85 1 RELAY 1 RELAY 2 MC3 CMITH 10 TB2 24v K 2 3 44 SET MC4 CM2TH ELECTRONIC aval CONTROL T GND HEAT CFS p 3 3 4 MC5 80 94 5 RED 374 HPS LPS L TC So gd A 85 86 03 ESRI 12 851 86 gt O 11 B2 D4 Y 85 86 P ESR EMITH EM2TH 30 7 14 3 4 CSS PES TB8 30 87 85 86 22 Bl 3 V1 5 85 86 L E B2 Y 85 86 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 JB 2 Figure 5 4 Electrical Schematic Wiring Diagram odel 68 40 504 13 D wg No 68RM 40 1094 Sheet 2 of 2 5 9 LINE SYMBOL DESCRIPTION 30 32 33 34 B BLOWER RELAYS 12 20 COOL RELAY 10 CBI CIRCUIT BREA
7. OFF TOUCH BAR CLIMATE Y PASS CONTROL SE S AUTOMATIC DRIVER CLIMATE CONTROL SWITCH PANEL LP BRIGHT_ OFF HEAT o Ab OFF TOUCH BAR BY PASS C VENT ae NORM LO DEFIHTR CLIMATE CONTROL DRIVER SELECT CLIMATE CONTROL SWITCH Figure 2 1 Unit Control Panel 2 1 2 3 Control Circuit The unit control circuit is 24 supplied by the bus 2 3 1 Air Conditioning Circuit Operation When the climate control switch is placed in the ON position 24 vdc power is supplied through the switch to terminal F of the temperature controller With the return air above 74_F the controller will energize the A C relay to close a set of normally open contacts This will send power to the A C terminal C of the controller From the following relays will energizes a Lock in Relay L Power will be supplied through the L ow Temperature Switch and the High and Low Pressure Switches to energize the Lock in Relay L Energizing the the L relay will close a set of normally open L contacts to allow power to energizethe Cool Relay C and Condenser Fan M otor Contactor Relay b Cool Relay C Energizing the Cool Relay C will close a set of normally open C contacts to activate the compressor clutch coil This will start the refrigerant cycle c Motor Contactor Relay MC3 Energizing the M otor Contactor Relay M C3 will close a set of normally o
8. De energized Circuit 20 21 22 23 24 25 24VDC e 8 1 CB3 1 ox 2 2 2 2 DRI 084 0 180 2 A2 ALG CBS MCS H 2 2 2 O DR2 85 86 CBE 0 220 2 A2 P FLOOR BLOWERS 2 30 87 EN Si os NOME CB2 W P ta 24VDC emm wm emm emm 71 DEF P TBS W p ng O I 2 G 85 86 WSV Ze DI GENS 1 TB13 P SWV 3 21 D E HEAT P TBI 1 IT v lt WATER VALVE 1 1 I DS CLUTCH RELAY 1 RELAY 2 L 162 24V J Al 06 GND RELAY 3 Ve TC VENT p DT 4 lt 2 K 2 4 3 4 P 7814 pa pL dex 30 87A 3 4 8 pos 30 87A 85 86 x 02 DE TBA e WTS gt V1 5 85 86 L 4 B2 AN 85 86 A Energized Circuit JB 2 SS De energized Circuit Figure 2 5 Air Conditioning M ode with Clutch C ycling Controller 2 5 20 21 22 23 24 25 24VDC emm e 8 1 1
9. parer vive 87 85 SEN RELAY 1 RELAY 2 MC3 CMITH 2 K A Ua 5 J MC4 CM2TH DA ELECTRONIC SUM CONTROL T MC2 GND HEAT CFS DB Y RELAY 3 3 44 MCS B A RED 374 TC HPS LPS L B B arde A 8577 86 D3 ESRI VENT 22 12 854 66 VE 7 gt o K 11 2 04 MCI 85 86 EMitH EM2TH 07 T A ESR2 7814 3 4 Ta Tu BI F TBS A 30 87A 85 86 22 Bl WE O gt J123 TB 85 86 L d B2 Y 85 86 Figure 5 5 Electrical Schematic Wiring Diagram M odel 68RM 40 504 27 D wg 68R 40 1134 Sheet 2 of 2 5 11 12 13 14 15 16 17 18 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 LINE 21 24 25 26 9 16 SC 1 21 22 25 GC TS N Ww A 14 20 14 16 20 20 2 22 2 21 4 17 5 18 4 19 2 23 25 18 23 17 18 21 8 10 CUSTOME 4 15 21 SYMBOL B CBI CB2 CB3 CB4 CB5 5 CM DRI DR2 EBS EM FPTS HPS LPS END DESCRIPTION BLOWER RELAYS COOL RELAY CIRCUIT BREAKER CIRCUIT BREAKER FLOOR HEATER 8 AMPS COOL amp WATER PUMP RELAY 15 AMP CIRCUIT BREAKER EVAP FAN MOTOR 1 35 AMPS CIRCUIT BREAKER EVAP FAN MOTOR 2 35 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR NO 1 50 AMPS
10. 1 CONTROL 3 44 P BP GND HEAT 1 3 1 9 SE Yes SC Jod RED TC T HPS LPS AP 854 86 CCS 82 EBS 03 MC2 EMTH EMTH L ve 25 To H O TOES SEI 2 1 30 87 12 TB12 nan Xd MCI Y 3 4 1 Y 87A 85 86 02 Br 4 WTS gt 85 85 L a B2 85 86 L Figure 5 1 Electrical Schematic Wiring Diagram odels 68R 40 504 amp 524 D wg 68RM 40 314 RevB Sheet 2 of 2 5 3 11 12 13 15 16 17 18 19 20 21 22 23 24 25 LINE 22 23 24 25 9 16 AU 2 3 23 14 20 14 16 20 20 2 22 2 21 4 17 5 18 4 19 2 20 17 18 21 8 10 5 4 15 17 NN D EN SYMBOL B 2 DESCRIPTION BLOWER RELAYS COOL RELAY CIRCUIT BREAKER FLOOR HEATER 8 AMPS CIRCUIT BREAKER COOL amp WATER PUMP RELAY 15 AMP CIRCUIT BREAKER EVAP FAN MOTOR NO 1 35 AMPS CIRCUIT BREAKER EVAP FAN MOTOR NO 2 35 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR NO 1 50 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 AMPS CONDENSER FAN SWITCH CONDENSER FAN MOTOR DIODE DROPPING RESISTOR EVAP MOTORS LOW SPEED DROPPING RESISTOR CONDENSER MOTORS LOW SPEED EVAP BLOWER MOTOR FLOOR BLOWER RE
11. 20 21 22 23 24 25 26 LINE SYMBOL DESCRIPTION 29 30 31 32 BLOWER RELAYS 13 20 COOL RELAY 10 CB1 CIRCUIT BREAKER FLOOR HEATER 8 AMPS 12 CB2 s CIRCUIT BREAKER COOL amp WATER PUMP RELAY 15 AMP 2 CB3 CIRCUIT EVAP FAN MOTOR 1 35 AMPS 4 4 CIRCUIT BREAKER EVAP MOTOR 0 2 35 AMPS 5 CIRCUIT BREAKER CONDENSER FAN MOTOR 1 50 AMPS 8 CBE CIRCUIT BREAKER CONDENSER FAN MOTOR NO 2 50 AMPS 24 CFS CONDENSER FAN SWITCH 6 8 CM CONDENSER FAN MOTOR 15 27 28 31 D DIODE 27 EBS 2 EVAP BLOWER SPEED SWITCH 2 4 EM E EVAP BLOWER MOTOR 27 28 ESR EVAP SPEED RELAY 10 30 F FLOOR BLOWER RELAY 18 FPTS FREEZE PROTECTION TEMPERATURE SWITCH 26 HPS HIGH PRESSURE SWITCH 18 20 26 LOCK IN RELAY 26 LPS LOW PRESSURE SWITCH 2 29 MOTOR CONTACTOR EVAP BLOWERS LOW SPEED 7 23 MC2 MOTOR CONTACTOR CONDENSER FAN 1 HIGH SPEED 5 21 MC3 SZ MOTOR CONDENSER NO 1 LOW SPEED 8 22 MC4 MOTOR CONTACTOR CONDENSER FAN 2 LOW SPEED 9 25 MCS MOTOR CONTACTOR CONDENSER FAN NO 2 HIGH SPEED CONNECTOR PLUG 2 PTB POWER TERMINAL BLOCK TB TERMINAL BLOCK 18 TC TEMPERATURE CONTROLLER REHEAT 21 22 29 TH THERMAL OVERLOAD PROTECTORS 2 14 W CUSTOMER SUPPLIED COMPONENTS 8 19 ACFL FAULT LIGHT 29 A C UNIT CIRCUIT BREAKE
12. Refrigerant Recovery Unit Refrigerant Cylinder Evacuation Manifold Valve Vacuum Pump Vacuum Gauge Compressor Suction Valve Discharge Valve 10 11 12 13 Condenser Evaporator Receiver Filter Drier Outlet Valve Figure 4 2 Vacuum Pump Connections 4 3 1 Removerefrigerant using a refrigerant recovery system 2 The recommended method is connecting three lines 3 8 OD copper tubing or larger to manifold Attach one line to the filter drier outlet valve compressor suction and discharge service valves See Figure 4 2 3 Connect lines to unit and manifold and make sure vacuum gauge valve is closed and vacuum pump valve is open 4 Startvacuum pump Slowly open valves halfway Then open vacuum gauge valve 5 Evacuateunituntil vacuum gauge indicates 1500 microns 29 86 inches 2 75 8 cm Hg vacuum Close gauge valve vacuum pump valve and stop vacuum pump 6 Break the vacuum with clean dry refrigerant Use refrigerant that the unit calls for Raise system pressure to approximately 2 psig 7 Removerefrigerant using a refrigerant recovery system 8 Start vacuum pump and open all valves D ehydrate unit to 500 microns 29 90 inches 75 9 cm H g vacuum 9 Close off pump valve and stop pump Wait five minutes to see if vacuum holds 10 With a vacuum still in the unit the refrigerant charge may be drawn into the system from a refrigerant container on weight scales 4 6 ADDIN
13. Loose bulb Superheat setting too low Ice holding valve open Foreign material in valve Pin and seat of expansion valve eroded or held open by foreign material Broken capillary Improper bulb location or loose bulb installation Low superheat setting NOTE Referto 05G Compressor manual Form T 199 3 2 Replace motor Check Replace Replace Check Replace Replace Replace Check Check Check Section 5 4 4 amp 4 6 Check 4 5 4 10 Replace Replace 4 10 Check 4 10 4 10 4 10 4 10 4 10 4 10 4 10 4 SERVICE WARNING Beware of rotating fan blades and unannounced starting of fans 4 1 MAINTENANCE SCHEDULE UNIT OPERATION or mmm a Daily Maintenance Pre trip inspection after starting b Weekly Inspection and Maintenance Perform daily inspection Check condenser evaporator coils and air filters Check refrigerant hoses and compressor shaft seal for leaks X Feel filter drier for excessive temperature drop across drier c Monthly Inspection and Maintenance Perform weekly inspection and maintenance Check tension and condition of V belt s Clean evaporator drain pan and hose s Check wire harness for chafing and loose terminals Check fan motor bearings Check compressor mounting bolts for tightness Check fan motor brushes 4 2 INSTALLING MANIFOLD GAUGES The manifold gauge set can be used to determine System operation pressure add charge eq
14. 18 5 1 30 1 28 22 6 19 9 1 40 1 37 24 4 214 1 50 1 48 26 3 22 9 1 61 1 58 28 2 24 5 1 72 1 69 30 1 26 1 1 84 1 80 32 0 27 8 1 95 1 92 34 11 29 6 2 08 2 04 36 2 313 2 20 2 16 38 3 332 2 33 2 29 40 4 35 1 2 47 2 42 45 7 401 2 82 2 76 50 10 45 5 3 20 3 14 55 13 512 3 60 3 53 60 16 57 4 4 04 3 96 65 18 64 1 4 51 4 42 70 21 71 1 5 00 4 90 75 24 78 7 5 53 5 43 80 27 86 7 6 10 5 98 85 29 95 3 6 70 6 57 90 32 104 3 7 33 7 19 95 35 114 0 8 01 7 86 100 38 124 2 8 73 8 56 105 41 135 0 9 49 9 31 110 43 146 4 10 29 10 09 115 46 158 4 11 14 10 92 120 49 171 2 12 04 11 80 125 52 184 6 12 98 12 73 130 54 198 7 13 97 13 70 135 57 213 6 15 02 14 73 140 60 229 2 16 11 15 80 145 63 245 6 17 27 16 93 150 66 262 9 18 48 18 13 155 68 281 1 19 76 19 37 5 ELECTRICAL SCHEMATIC WIRING DIAGRAM 5 1 INTRODUCTION This section contains Electrical Schematic Wiring Diagram covering the M odels listed in Table 1 1 The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this manual They are conne precautions that must be understood and applied during operation and maintenance of the equipment covered herein WARNING Beware of rotating fan blades and unannounced starting of fans WARNING Do not use a nitrogen cylinder without a pressure regulator Do not use oxygen in or near a refrigeration system or as an explosi
15. 4 17 5 18 4 19 2 20 17 18 21 8 10 CUSTOME 4 15 17 LO N SYMBOL B 1 CB2 CB3 CB4 CB5 CBB CFS CM D DRI DR2 EM HPS LPS MC1 MC2 MC3 MC4 MC5 PTB TB TC TH END DESCRIPTION BLOWER RELAYS COOL RELAY CIRCUIT BREAKER CIRCUIT BREAKER FLOOR HEATER 8 AMPS COOL amp WATER PUMP RELAY 15 AMP CIRCUIT BREAKER EVAP FAN MOTOR NO 1 35 AMPS CIRCUIT BREAKER EVAP FAN MOTOR 0 2 35 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR NO 1 50 AMPS CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 AMPS CONDENSER FAN SWITCH CONDENSER FAN MOTOR DIODE DROPPING RESISTOR EVAP MOTORS LOW SPEED DROPPING RESISTOR CONDENSER MOTORS LOW SPEED EVAP BLOWER MOTOR FLOOR BLOWER RELAY HEAT RELAY HIGH PRESSURE SWITCH LOCK IN RELAY LOW PRESSURE SWITCH MOTOR CONTACTOR EVAP BLOWER LOW SPEED MOTOR CONTACTOR EVAP BLOWER HIGH SPEED MOTOR CONTACTOR CONDENSER FAN NO 1 MOTOR CONTACTOR CONDENSER FAN 2 MOTOR CONTACTOR CONDENSER FAN HIGH SPEED CONNECTOR PLUG POWER TERMINAL BLOCK TERMINAL BLOCK TEMPERATURE CONTROLLER CYCLING CLUTCH THERMAL OVERLOAD PROTECTORS WATER PUMP RELAY SUPPLIED COMPONENTS A C FAULT LIGHT A C UNIT CIRCUIT BREAKER A C COMPRESSOR CLUTCH COIL 4 POSITION CLIMATE CONTROL SW DRIVER DEFROST SWITCH 4 POSITION CLIMATE CONTROL SW HIGH SPEED BLOWER SWITCH SIDE WATER VALVE
16. High Pressure 5 Bottom Plate Switch Connection 6 Oil Drain Plug 2 Low Pressure 7 Oil Sight Glass Switch Connection 8 Oil Pump 3 Suction Service 9 Pressure Unloader Valve 10 Discharge Service 4 Oil Fill Plug Valve Figure 4 6 O5G Compressor 4 11 2 Compressor Oil Level a Checking the Compressor Oil L evel 1 Start the unit and allow the system to stabilize 2 Check the oil sight glass on the compressor to ensure that no foaming of the oil is present after 20 minutes of operation If the oil is foaming excessively after 20 minutes of operation check the refrigerant system for flood back of liquid refrigerant Correct this situation before proceeding 3 Check the level of the oil in the front sight glass with the compressor operating the correct level should be between 1 4 and 1 2 of the sight glass If the level is above 1 2 oil must be removed from the compressor To remove oil from the compressor follow step d If thelevel is below 1 8 add oil to the compressor following step b b AddingOil with Compressor in System Two methods for adding oil are the oil pump method and closed system method 1 Oil Pump M ethod One compressor oil pump that may be purchased isa Robinair part no 14388 This oil pump adapts to a one U S gallon 3 785 liters metal refrigeration oil container and pumps 2 1 2 ounces 0 0725 liters per stroke when connected to the suction service valve port Also there is no need to remove pu
17. 26 32 75 0 5 27 5 17 24 31 81 4 5 72 5 61 22 30 88 1 6 19 6 07 20 29 91 5 6 43 6 31 18 28 102 5 7 21 7 07 16 27 110 2 7 75 7 6 14 26 118 3 8 32 8 16 12 24 126 8 8 91 8 74 10 23 135 7 9 54 9 36 8 22 145 10 19 10 0 21 154 7 10 88 10 67 4 20 164 9 11 59 11 37 2 19 175 4 12 33 12 09 0 18 186 5 13 11 12 86 2 17 197 9 13 91 13 64 4 16 209 9 14 76 14 47 6 14 222 3 15 63 15 33 8 13 235 2 16 54 16 22 10 12 248 7 17 49 17 15 12 11 262 6 18 46 18 11 14 10 277 0 19 48 19 10 16 9 291 8 20 52 20 12 18 8 307 1 21 59 21 17 20 7 323 6 22 75 22 31 22 6 341 3 24 0 23 53 24 4 359 4 25 27 24 78 26 3 377 9 26 57 26 06 28 2 396 6 27 88 27 34 30 1 415 6 29 22 28 65 32 0 434 6 30 56 29 96 4 8 Table 4 2 R 134a Temperature Pressure Chart BOLD NO Inches Mercury Vacuum cm Hg Vac Temperature PRESSURE _F PSIG Kg cm2 Bar 40 40 14 6 37 08 0 49 35 37 123 31 25 0 42 30 34 9 7 24 64 0 33 25 32 6 7 17 00 0 23 20 29 3 5 8 89 0 12 18 28 2 1 5 33 0 07 16 27 0 6 1 52 0 02 14 26 0 4 0 03 0 03 12 24 1 2 0 08 0 08 10 23 2 0 0 14 0 14 8 22 2 9 0 20 0 20 6 21 3 7 0 26 0 26 4 20 4 6 0 32 0 32 2 19 5 6 0 39 0 39 0 18 6 5 0 46 0 45 2 17 7 6 0 53 0 52 4 16 8 6 0 60 0 59 6 14 9 7 0 68 0 67 8 13 10 8 0 76 0 74 10 12 120 0 84 0 83 12 11 13 2 0 93 0 91 14 10 14 5 1 02 1 00 16 9 15 8 1 11 1 09 18 8 171 1 20 1 18 20 7
18. CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 AMPS CONDENSER FAN SWITCH CONDENSER FAN MOTOR DIODE DROPPING RESISTOR EVAP MOTORS LOW SPEED DROPPING RESISTOR CONDENSER MOTORS LOW SPEED EVAP BLOWER SPEED SWITCH EVAP BLOWER MOTOR FLOOR BLOWER RELAY FREEZE PROTECTION TEMPERATURE SWITCH HIGH PRESSURE SWITCH LOCK IN RELAY LOW PRESSURE SWITCH MOTOR CONTACTOR EVAP BLOWER LOW SPEED MOTOR CONTACTOR EVAP BLOWER HIGH SPEED MOTOR CONTACTOR CONDENSER FAN NO 1 MOTOR CONTACTOR CONDENSER FAN NO 2 MOTOR CONTACTOR CONDENSER FAN HIGH SPEED CONNECTOR PLUG POWER TERMINAL BLOCK BLOWER INTERLOCK SWITCH RELAY TERMINAL BLOCK TEMPERATURE CONTROLLER REHEAT TIME DELAY THERMAL OVERLOAD PROTECTORS WATER PUMP RELAY SUPPLIED COMPONENTS ACFL CB 5 DEF PRT SWV WP WSV WTS A C FAULT LIGHT A C UNIT CIRCUIT BREAKER A C COMPRESSOR CLUTCH COIL CLIMATE CONTROL SWITCH DRIVER DEFROST SWITCH PARTICULATE TRAP CONTROL SIDE WATER VALVE HEATER WATER PUMP WATER SOLENOID VALVE MAIN WATER VALVE WATER TEMPERATURE SWITCH ENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING Figure 5 6 Electrical Schematic Wiring Diagram M odel 68RM 40 504 23 D wg 68 40 1154 Sheet 1 of 2 5 12 24VDC
19. Ee Ee Men IE 32 UnitRunsBut has Insufficient Cooling 3 9 Abnormal Pressure oce EET eet eun 34 Abnormal Noise and Vibrations 3 41 Abnormal Noise rone meet Det em eet PIU 342 Abnormal Vibration e ai 35 Temperature Controller Malfunction 36 No Evaporator Air Flow Restricted Flow 37 Expansion Valve Malfunction 4 SERVICE sis nee niet rare aaa e ee E 41 Maintenance Schedule 42 Installing M anifold Gauges 2 43 Pumping The System Down or Removing The Refrigerant Charge 4 3 1 Sytem PUMA DOW ees ce nh eee menace ee p e e REC es 43 2 Removingthe Refrigerant Charge 44 Refrigerant Leak 2 45 Evacuation Dehydration 46 Adding Refrigerant To System 4 6 1 AddingFull Charge 46 2 Adding Partial Charge 47 Checking For 5 5 nnn 48 Checking a
20. HEAT RELAY HIGH PRESSURE SWITCH LOCK IN RELAY LOW PRESSURE SWITCH MOTOR CONTACTOR EVAP BLOWER LOW SPEED MOTOR CONTACTOR EVAP BLOWER HIGH SPEED MOTOR CONTACTOR CONDENSER FAN NO 1 MOTOR CONTACTOR CONDENSER FAN 2 MOTOR CONDENSER FAN HIGH SPEED CONNECTOR PLUG POWER TERMINAL BLOCK TERMINAL BLOCK TEMPERATURE CONTROLLER REHEAT THERMAL OVERLOAD PROTECTORS WATER PUMP RELAY SUPPLIED COMPONENTS A C FAULT LIGHT A C UNIT CIRCUIT BREAKER A C COMPRESSOR CLUTCH COIL 4 POSITION CLIMATE CONTROL SWITCH DRIVER DEFROST SWITCH 4 POSITION CLIMATE CONTROL SWITCH HEAT SIDE WATER VALVE HEATER 4 POSITION CLIMATE CONTROL SWITCH VENT WATER PUMP WATER SOLENOID VALVE MAIN WATER VALVE WATER TEMPERATURE SWITCH ENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING Figure 5 4 Electrical Schematic Wiring Diagram M odel 68RM 40 504 13 D wg No 68RM 40 1094 Sheet 1 of 2 5 8 24VDC 12 13 JB 1 PTBI dba 11172 1 2 ESRI p EMI 30 t 87A 4 51 DG A2 L 1 2
21. RM40504 40 504 1 Cycling Clutch 40 504 3 Cycling Clutch 40 504 5 40 504 4 Clutch 40 504 7 Cycling Clutch RN O SO4 CO mz NONE ce 1 1 APUNE Org 00000000 00090900009 000000060 5 5 VIEW CURBSIDE CS e L Condenser Coil Evaporator Blower Shroud Heater Coil See Figure 1 4 Wire Connection to Main Water Valve Assembly Evaporator Blower Motor Receiver Outlet Valve Filter Drier 13 14 Receiver Sight Glass High Pressure Switch Low Pressure Switch Suction Line Service Port Suction Line Connection to Compressor Thermostatic Expansion Valve Figure 1 1 Unit Assembly Back View 1 2 15 16 17 18 19 20 21 Condenser Fan Switch Filter Drier Outlet Valve Access Panel Discharge Line Service Port Discharge Line Connection to Compressor Discharge Line Check Valve Condenser Fan Motor Upper Mounting Bracket 7 Controller 1 2 3 4 5 6 240 Watt Resistor 8 Harness Te
22. circuit breaker CB TEMPERATURE CONTROLLER TC WITH REHEAT TC TERMINALS TEMPERATURE CONTROLLER TC WITH CYCLING CLUTCH OPERATING TC TERMINALS MODE ES NOTE Terminal F is input and terminal A is ground for the TC L Power supplied from TC to Terminal NO Power from With the Reheat controller the water pump and valve will cycle on and off during the reheat mode With the Cycling Clutch controller the compressor clutch will cycle on and off during the reheat mode 2 3 2 Ventilation Circuit Operation 24 vdcflowsthrough the main circuit breaker CB to the Vent Switch When the Vent switch is placed in the VENT position 24 vdc power is fed from the switch to energizes the Motor Contactors amp M C2 Energizing the MC will close a set of normally open MC contacts to allow power to start the Evaporator Blower Motors EM 2 3 3 Heating O peration 24 vdcflowsthrough the main circuit breaker CB to the H eat Switch When the Heat switch is placed in the HEAT position 24 vdc power is fed from the switch to temperature controller TC 2 2 CONDITIONING High Speed Blowers VENT ONLY Low Speed Blowers HEAT Low Speed Blowers Temperature Rise AIR CONDITIONING High Speed Blowers REHEAT amp AIR CONDITIONING High Speed Blowers HEAT Low Speed Blowers Temperature Fall Figure 2 2 Temperature Controller Seq
23. parallel and then secure loosened clamp making sure both bulbs are firmly secured to suction line Replace Presstite around bulb 4 Connect an accurate gauge to the 1 4 port on the suction service valve 5 Rununituntil unit has stabilized NOTE When conducting this test the suction pressure must be at least 6 psig 42 kg cm below the expansion valve maximum operating pressure M OP Refer to section 1 2 for 6 Fromthetemperature pressure chart determine the saturation temperature corresponding to the evaporator outlet pressure Add an estimated suction line loss of 2 psig 14 kg cm to the figure 4 5 7 Note temperature of the suction gas at the expansion valve bulb Subtract the saturation temperature determined in Step 6 from the average temperature measured in Step 7 The difference is the superheat of the suction gas c Adjusting Superheat l Power Head 7 Bulb 2 Cap Seal 8 Gasket 3 Flare Seal 9 Cage Assembly 4 Retaining Nut 10 Body Flange 5 Adjusting Stem 11 Capscrew 6 Equalizer Connection Figure 4 4 Thermostatic E xpansion Valve 1 Remove hex cap from side of TXV power head Thiswill expose the adjusting stem which has screw slot 2 With a screwdriver turn the adjusting stem clockwiseto increase superheat turn counterclockwiseto reduce superheat A pproximately 2 turns of the adjusting stem will change super heat 1 ake adjustment slowly to give the valve a chance
24. 12 1 2 d A2 CO la DRI 0 180 1 2 2 gt Ai te MC3 CBS MCS pa FaN H Ee CM1 11 1112 1 2 2 _ 2 112 082 85 86 MC4 CBE 0 22 2 1112 1 2 2 A1 AN F K FLOOR BLOWERS 1 2 301 187 al 4 Sdi 2 Re vx 3 WP 1 2 87 b 24VDC 3 LLCS cB DEF d 5 W i gt Li 4 C 1 2 85 86 WSV Ze Di LA 1 TB13 CB 3 5 H 2 SN ven t app EIS D E C 3 ma T Lr riim A hee 2 E TBI Lire gt 1 Ge EE tro tto L F 1 d 05 Z WATER VALVE 30 87 85 85 ius RELAY 1 RELAY 2 MC3 CMTH P TB2 24v K E 5 J EET CH CMTH ELECTRONIC d CONTROL 374 ur GND HEAT 06 SZ I RELAY 3 10 die DN LY E B A 3 4 RED 5 1 5 L 1 11 Su 85 86 VENT D3 y MC2 EMTH EMTH DT 2 Se cane k GENIE 3 74 P pu 0 30 87A 374 4 3 87A 85 86 02 DI TB4 3 BER 85 85 L B2 ON 85 86 JB 2 Figure 5 2 Electrical Schematic Wiring Diagram M odel 68RM 40 504 5 D wg No 68R M 40 1054 Sheet 2 of 2 5 5 20 21 22 23 24 25 LINE 22 23 24 25 9 16 AU wNOO 3 23 14 20 14 16 20 20 2 22 2 21
25. 2 K sete a J coe CM2TH ELECTRONIC F CONTROL 4 2 GND HEAT Y L RELAY 3 3 7 4 MCS RED lan TC B x LPS L 324 5 d A BS HG EBS DV ESR1 O t 2 TB12 11 85 86 ESR2 DI ccs 82 5 86 EMITH EM2TH Le 1 2 2 4 30 87A pp 3 4 1 8 87A 85 86 N 02 4 WTS BER 85 86 J B2 85 86 MILA JB 2 Figure 5 7 Electrical Schematic Wiring Diagram M odel 68RM 40 524 11 D wg 68R M 40 1114 Sheet 2 of 2 5 15 5 16 20 21 22 23 24 25 26 27 28 23 30 31 32
26. CHEATER 4 POSITION CLIMATE CONTROL SW WATER PUMP WATER SOLENOID VALVE MAIN WATER VALVE WATER TEMPERATURE SWITCH CENGINE TCH CA C TCH CHEAT TCH VENT INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING Figure 5 3 Electrical Schematic Wiring Diagram M odel 68R M 40 504 3 amp 504 7 Dwg No 68R M 40 1064 Sheet 1 of 2 5 6 24VDC o JB 1 MC1 CB3 MC2 PTB2 1 M 1112 1 2 7 A2 CO 112 DRI 0 180 T 1 2 420 Ai te MC3 CBS MCS po 11 1112 1 2 AI 7 A2 CO DR2 85 86 MC4 ca GA 0 220 fila 1 2 420 A1 M FLOOR BLOWERS 1 2 30 87 al ps V i MUN CB2 W P 7 ako vx 3 WP z 1 2 301 87 be 24VDC SS gt LCOS 30 TBS W p Y LE lt 13 85 86 WSV Ze DI 1 TB13 P SWV A d 3 2 H hc 4 89 l ACFL H G gt So EROR riim _ ACFL2 1 5 4 D WATER VALVE I GE GREEN lan 05 30 87 85 85 RELAY 1 RELAY 2 I MC3 CMTH COOL TB2 YELLOW lan vu WG lt
27. EATER 28 VENT 4 POSITION CLIMATE CONTROL SWITCH CVENT 11 WP i WATER PUMP 5 WSV WATER SOLENOID VALVE MAIN WATER VALVE 33 WTS WATER TEMPERATURE SWITCH CENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING Figure 5 5 Electrical Schematic Wiring Diagram M odel 68RM 40 504 27 D wg 68R 40 1134 Sheet 1 of 2 5 10 24VDC i MN E PTB2 11 A L 112 1 2 ESRI 7 EMI 87 4 51 AX A2 L 1 2 Ces 7 em 87A MC3 CBS 2 51 s 1 2 N 932 112 MC2 MC4 CBE Al 51 IX 2 5 72 2 __s37 LE MS P P FLOOR BLOWERS 1 2 30 8 M TUUM A TN SS CB2 A pra Bed gt WPF 1 2 87 c V C P CC 3 reo 24VDC 30 87 D DEF 5 W D TU O 1 2 6 85 86 WSV ANA 7813 SUV gt H 2 D E A To E 4 gt iis TS L Pus gt ACFL2 AM AL Coreen 7 YELLOW 4 1 1 AUN Pla dp L Co VE N d d 7 DTSS
28. G REFRIGERANT TO SYSTEM 4 6 1 Adding Full Charge a Evacuate and dehydrate system refer to section 4 5 b Place appropriate refrigerant cylinder on scales and connect charging hose from container to filter drier inlet valve Note weight of refrigerant and container d Open liquid valve on refrigerant container M idseat filter drier inlet valve and allow refrigerant to flow into the unit Correct charge will be found in section 1 2 e When drum weight scale indicates that the correct charge has been added close liquid line valve on drum and backseat the filter drier inlet valve 4 6 2 Adding Partial Charge a Start the vehicle engine and allow unit to stabilize b Place appropriate refrigerant cylinder on scales and connect charging hose from container vapor valve to filter drier inlet valve or compressor suction service valve C Open service valve and add charge until level appears at center of lower receiver sight glass d Backseatsuction service valve Close vapor valve on refrigerant drum and note weight Replace all valve Caps 4 7 CHECKING FOR NONCONDENSIBLES To check for noncondensibles proceed as follows a Stabilize system to equalize pressure between the suction and discharge side of the system b Check temperature at the condenser and receiver C Check pressure at the compressor discharge service valve d Check saturation pressure as it corresponds to the condenser receiver tempe
29. KER FLOOR HEATER 8 AMPS 11 CB2 CIRCUIT BREAKER COOL amp WATER PUMP RELAY 15 AMP 2 CIRCUIT BREAKER EVAP FAN MOTOR 1 35 AMPS 4 CIRCUIT BREAKER EVAP FAN MOTOR NO 2 35 AMPS 6 CBS CIRCUIT BREAKER CONDENSER FAN MOTOR 1 50 AMPS 8 CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 5 24 CFS ET CONDENSER FAN SWITCH 5 7 8 8 CM CONDENSER FAN MOTOR D DIODE 2 4 EM BLOWER MOTOR 3 5 27 29 ESR EVAP SPEED RELAY 10 32 F FLOOR BLOWER RELAY 16 FPTS FREEZE PROTECTION TEMPERATURE SWITCH 26 HPS HIGH PRESSURE SWITCH 18 20 26 L LOCK IN RELAY 26 LPS LOW PRESSURE SWITCH 2 30 MC1 SC MOTOR CONTACTOR EVAP BLOWER LOW SPEED 7 23 MC2 MOTOR CONTACTOR EVAP BLOWER HIGH SPEED 6 21 MC3 MOTOR CONDENSER NO 1 8 22 MC4 MOTOR CONTACTOR CONDENSER FAN 2 9 25 MCS MOTOR CONTACTOR CONDENSER FAN HIGH SPEED CONNECTOR PLUG 26 PTB Ee POWER TERMINAL BLOCK TB TERMINAL BLOCK 20 TC TEMPERATURE CONTROLLER REHEAT 17 18 21 TH THERMAL OVERLOAD PROTECTORS 19 5 CONNECTOR TEMPERATURE SELECTOR 11 14 W WATER PUMP RELAY CUSTOMER SUPPLIED COMPONENTS 18 19 ACFL A C FAULT LIGHT 4 16 CB A C UNIT CIRCUIT BREAKER 2 A C COMPRESSOR CLUTCH COIL 21 COOL e 4 POSITION CLIMATE CONTROL SWITCH 4 DEF DRIVER DEFROST SWITCH 20 DTSS DRIVER TEMPERATURE SELECTOR SWITCH CAM PM 6 SWV Se SIDE WATER VALVE CH
30. LAY HEAT RELAY HIGH PRESSURE SWITCH LOCK IN RELAY LOW PRESSURE SWITCH MOTOR CONTACTOR EVAP BLOWER LOW SPEED MOTOR CONTACTOR EVAP BLOWER HIGH SPEED MOTOR CONDENSER FAN NO 1 MOTOR CONTACTOR CONDENSER FAN 2 MOTOR CONDENSER FAN HIGH SPEED CONNECTOR PLUG POWER TERMINAL BLOCK TERMINAL BLOCK TEMPERATURE CONTROLLER REHEAT THERMAL OVERLOAD PROTECTORS WATER PUMP RELAY SUPPLIED COMPONENTS ACFL CB COOL DEF HEAT HSS SWV VENT WP WSV WTS A C FAULT LIGHT A C UNIT CIRCUIT BREAKER A C COMPRESSOR CLUTCH COIL 4 POSITION CLIMATE CONTROL SWITCH DRIVER DEFROST SWITCH 4 POSITION CLIMATE CONTROL SWITCH CHEAT HIGH SPEED BLOWER SWITCH SIDE WATER VALVE CHEATER 4 POSITION CLIMATE CONTROL SWITCH VENT WATER PUMP WATER SOLENOID VALVE MAIN WATER VALVE WATER TEMPERATURE SWITCH ENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS WIRING Figure 5 2 Electrical Schematic Wiring Diagram M odel 68R M 40 504 5 D wg No 68R M 40 1054 Sheet 1 of 2 5 4 24VDC ES BET E E 11 11
31. R 3 COMPRESSOR CLUTCH COIL 29 5 CLIMATE CONTROL SWITCH 14 DEF DRIVER DEFROST SWITCH 6 SWV SIDE WATER VALVE HEATER 2 WP WATER PUMP 5 WSV 2 2 WATER SOLENOID VALVE MAIN WATER VALVE 31 WTS WATER TEMPERATURE SWITCH ENGINE INDICATES CUSTOMER SUPPLIED COMPONENTS amp WIRING Figure 5 7 Electrical Schematic Wiring Diagram M odel 68RM 40 524 11 Dwg No 68RM 40 1114 Sheet 1 of 2 5 14 24VDC o JB 1 ind ES d 2 C DG L 2 1 2 ESRI 7 em 874 CB4 51 A x 1 2 ESR2 BD EM2 F 874 5 2 51 2 1 2 INE MC4 CBE Al 51 TR 7X 2 5 2 7072 2 _s3 P FLOOR BLOWERS x 3 1 2 30 87 M 2 7 gt SEA CB2 DON WP 1 2 87 C b 24VDC H gt pu DEF e TBS W 87 D Me 25 85 86 SV 201 TB13 SWV 3 ERAS H FPTS ALI 9 3 2 T 1 cx Ie YELLOW 4 ie pit F Mater VALVE A 86 RELAY 1 RELAY 2
32. TRANSICOLD Bus Air Conditioning Unit Rearmount 68RM40 504 68RM40 514 68RM40 524 OPERATION AND SERVICE TRANSICOLD OPERATION AND SERVICE MANUAL BUS AIR CONDITIONING UNIT Rearmount 68RM40 504 68RM40 514 68RM40 524 mm UNITED TECHNOLOGIES gt CARRIER TRANSICOLD TABLE OF CONTENTS Section 1 DESCRIPTION TL INEFOQUCHIONI ilaele re eg See inno 12 Refrigeration System Component Specifications 13 Electrical Specifications L4 Safety Devices iiie et reo Eb eb Ne ed 15 System Operating Controls and lt 16 Heater Cycle ie oerte e operas t Pa eti diea nece te PARTE 17 Air Conditioning Refrigerant Cycle 2 OPERATION 21 Pre trip IMSpeltion ix ree ber des E Ha TE Race rage sh 22 Startingand Stopping Instructions 2232 Control Circuits 25 000 Wed a ae 23 1 Air Conditioning Circuit 2 3 2 Ventilation Circuit Operation 2 33 HeatingOperation 2 3 TROUBLESHOOTING 31 UntWIllNOEGCOOl o EE er
33. When ventilation onlyisselected onlythe evaporator blowers function to circulate air throughout the bus The refrigerant cycle will remain off 4 c 11 me UN PR 1 8 Compressor i Discharge Line Discharge Line Check Valve Condenser Coil 5 Filter Drier Inlet Service Valve Filter Drier Filter Drier Outlet Service Valve Thermostatic Expansion Valve Evaporator Coil Suction Line 7 A gt gt d Y gt lt I Y 5 1 2 fo Figure 1 5 Air Conditioning Cycle 2 OPERATION 2 1 PRE TRIP INSPECTION After starting unit allow system to stabilize 10 to 15 minutes and proceed as follows 1 Listen for abnormal noises to section 3 4 2 Check compressor oil level 3 Check refrigerant level 2 2 STARTING AND STOPPING INSTRUCTIONS a Starting 1 Start the vehicle engine 2 Place the climate control switch in the ON position b Stopping 1 Place the climate control switch in the OFF position NOTE Besure air conditioningunit isturned off before stopping the engine PANEL LP
34. adjusting the suction service valve as necessary I Reinstall the sealing caps that cover the differential adjustment screws and tighten NOTE On models equipped with unloader adjustment jam nuts turn these nuts CCW up tightly against the load up adjustment hex nut to lock in unloader valve adjustment m Backseat both suction and discharge service valves turn CCW and disconnect manifold gauge set 4 13 ELECTRIC COMPRESSOR UNLOADER The pressure switches U PS1 amp U PS2 settingsarein If Equipped section 1 2 The electric unloaders internal operation is similar 24V to that of the pressure activated unloaders except that A instead of being activated by the suction pressure the UL electric unloaders are activated by an electromagnetic OTO wor coil which is energized by a pressure switch monitoring UPS1 suction pressure See Figure 4 7 p g fo Nr Two pressure switches mounted on the compressor SE each switch operating one unloader control voltage to UPS2 the unloader coil When suction pressure gets to set E pointof the pressure switch it energizesthe unloader coil which activates unloading in the compressor head Figure 4 7 Electric Unloader Schematic Table 4 1 R 22 Pressure Temperature Chart TEMPERATURE PRESSURE TEMPERATURE PRESSURE _ Psig Kg cm Bar _F 2 Kg cm 40 40 60 5 4 25 4 17 36 38 63 3 4 45 4 36 32 36 66 1 4 65 4 56 28 33 69 4 85 4 76
35. cuit breaker CB senses excessive current draw by the TC or one of theoperating components During the reheat mode operation will automatically stop in the same manner asindicated in the vent or heat modes The evaporator condenser and floor heater motors are protected independently against high current draw with circuit breakers CB3 4 5 amp 6 The evaporator and condenser motors are also protected from high temperature with thermal protection switches IP and If one of the evaporator motor safety devices opens to stop one or both of the motors low pressure may become present in the system which may cause the low pressure switch LPS to open shuttingthe unit down If a condenser motor safety device opens high pressure may be become present which may open the high pressure switch H PS to shut the unit down When a safety device opens and causes the unit operation to stop place the climate control switch to off position before resolving the problem T he safety device may need to be manually reset before restarting the unit Unsafe Condition Excessive current draw by the floor heater blowers Excessive current draw by the water pump or clutch coil Excessive current draw by evaporator motor no 1 Excessive current draw by evaporator motor no 2 Excessive current draw by condenser motor no 1 Excessive current draw by condenser motor no 2 High compressor dischar
36. e deadly enemy of refrigerant systems 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 in metal corrosion b Preparation 1 Evacuate and dehydrate only after pressure leak test Refer to section 4 4 2 Essential tools to properly evacuate and dehydrate any system include a good vacuum pump minimum 5 cfm 2 8 cu m volume displacement CTD P N 07 00176 01 and a good vacuum indicator such asa thermocouple vacuum gauge vacuum indicator available through Robinair M anufacturing M ontpelier Ohio Part Number 14010 NOTE It isnot recommended using a compound gauge because of it s inherent inaccuracy 3 Keep the ambient temperature above 60 F 15 6 C to speed evaporation of moisture If ambient temperature is lower than 60 F 15 6 C ice may form before moisture removal is complete H eat lamps or alternate sources of heat may be used to raise system temperature Procedure for E vacuation and Dehydrating System a 10 AN 11
37. egulator valve to increase the pressure until it reaches cut out point The switch should open which is indicated by an infinite reading on an ohmmeter no continuity 4 4 f Close cylinder valve and release pressure through the bleed off valve A s pressure drops to cut in point the switch contacts should close indicating no resistance on the ommeter g Replace switch if it does not function as outlined above 1 Cylinder Valve and Gauge Pressure Regulator Nitrogen Cylinder Pressure Gauge 0 to 400 psig 0 to 36 kg cm Bleed Off Valve 1 4 inch Connection PN exul Figure 4 3 Checking High Pressure Switch 4 9 FILTER DRIER To Check Filter D rier If the sight glass on the receiver appears to be flashing or excessive bubbles are constantly moving through the sight glass the unit may have a low refrigerant charge or the filter drier could be partially plugged Check for a restricted or plugged filter drier by feeling the liquid line inlet and outlet connections of the filter drier If the outlet side feels cooler than the inlet side then the filter drier should be changed To Replace Filter D rier a Pump down the unit Refer to section 4 3 b Replace filter drier ensuring that the arrow on the filter drier points in the direction of the refrigerant flow c Check refrigerant level 410 THERMOSTATIC EXPANSION VALVE The thermal expansion valve is an automatic device which maintainsconstant sup
38. eplace Check R eplace Check See Note Check R eplace 14 See Note Check NO TAG 3 6 3 7 4 9 43 4 7 Check Clean Check Check See Note 4 4 amp 4 6 See Note O pen O pen 4 9 Check Clean Clean See Note INDICATION REFERENCE RD UBNERMAL NOISE POSSIBLE CAUSES SECTION Compressor Loosemountingbolts See Note 2 Worn bearings See Note Worn or broken valves See Note Liquid slugging 3 7 Insufficient oil 4 11 2 Clutch loose or rubbing Check Condenser or E vaporator fan Loose or defective Check A djust Bearings Replace Blade Interference Check Blade broken or missing Check 3 4 2 ABNORMAL VIBRATION Compressor Loose mounting bolts 3 41 Evaporator or Condenser fan Bent shaft on motor Blade broken or missing 3 5 TEMPERATURE CONTROLLER MALFUNCTION Will not control Controller defective Sensor defective D efective wiring 3 6 NO EVAPORATOR AIR FLOW OR RESTRICTED AIR FLOW No evaporator air flow M otor burnout Fan damage Brushes defective Return air filter dirty R1 amp R3 Relays defective 1 amp Fuses defective Wiring polarity incorrect 3 7 EXPANSION VALVE MALFUNCTION Low suction pressure with high superheat Low superheat and liquid slugging in compressor Fluctuating suction pressure Low refrigerant charge Wax oil or dirt plugging valve orifice Ice formation at valve seat Superheat setting too high Power assembly failure L oss of bulb charge Broken capillary
39. ergized Circuit Figure 2 7 Heat Mode with Clutch Cycling Controller 2 7 20 21 22 23 24 25 INDICATION TROUBLE 3 1 UNIT WILL NOT COOL Compressor will not run SECTION 3 TROUBLESHOOTING POSSIBLE CAUSES F5 Fuse defective 5 Relay defective V Belt defective Compressor malfunction Clutch malfunction Safety device open 3 2 UNIT RUNS BUT HAS INSUFFICIENT COOLING Compressor Refrigeration system 3 3 ABNORMAL PRESSURE High discharge pressure Low discharge pressure High suction pressure Low suction pressure Low evaporator air flow Suction and discharge pressures tend to equalize when unit is operating Compressor valves defective V belt loose A bnormal pressures No or restricted evaporator air flow Expansion valve malfunction Restricted refrigerant flow Refrigerant overcharge Noncondensibles in system Condenser fan motor rotation incorrect Condenser coil dirty R6 amp R7 Relays defective F6 amp F7 Fuses defective Compressor valves s worn or broken Low refrigerant charge Compressor valves worn or broken Suction service valve partially closed Receiver outlet valve partially closed Filter drier partially plugged Low refrigerant charge Expansion valve malfunction Restricted air flow Blower running in reverse Dirty air filter Icing of coil Compressor valves defective NOTE Refer 056 Compressor manual Form T 199 31 REFERENCE SECTION Check R
40. erheat of the refrigerant gas leaving the evaporator regardless of suction pressure The valve functions are a automatic response of refrigerant flow to match the evaporator load and b prevention of liquid refrigerant entering the compressor U nless the valve is defective it seldom requires any maintenance a Replacingthe Expansion Valve 1 Pump down the unit Refer to section 4 3 2 Remove insulation Presstite from expansion valve bulb and then remove bulb from suction line 3 Loosen flare nut and disconnect equalizer line from expansion valve 4 Remove flange screws and lift off power assembly Then remove the cage assembly Check for foreign material in valve body 5 Thethermal bulb is located below the center of the suction line 4 or 7 o clock position This area must be clean to ensure positive bulb contact Strap thermal bulb to suction line and insulate both with Presstite 6 Install new gaskets and insert cage assembly and install power assembly 7 Fasten equalizer tube to expansion valve 8 Evacuate by placing vacuum pump on suction service valve 9 Open filter drier inlet valve and then check refrigerant level Refer to section 4 6 2 10 Check superheat b To Measure Superheat 1 Remove Presstite from expansion valve bulb and suction line 2 LoosenoneTXV bulb clamp and make sure area under clamp above TXV bulb is clean 3 Place temperature thermocouple on top of the TXV bulb
41. etain the original unloader valves for use on 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 3 Do not interchange allen head cap screws that mount the piston plug and unloader they are not interchangeable 4 Check oil level in service replacement compressor R efer to section 1 2 and 4 11 2 GASKET SPRING COMPRESSOR READ D WW IE BYPASS FLANGE SCREWS PISTON COVER NOT INTERCHANGEABLE PLUG WITH CONTROL VALVE SCREWS Figure 4 5 Removing Bypass Piston Plug f Removethehigh and low pressure switch assembly and install on new compressor after checking switch setting g Install compressor in unit by reversing steps b through g It is recommended using new locknuts when replacing compressor Install new gaskets on service valves and tighten bolts uniformly h Attach two lines with hand valves near vacuum pump to the suction and discharge service valves Dehydrate and evacuate compressor to 500 microns 29 90 Hg vacuum 75 9 cm Hg vacuum Turn off valves on both linesto pump i Fully backseat open both suction and discharge service valves Remove vacuum pump lines and install manifold gauges k Start unit and check refrigerant level Check compressor oil level Refer to section 4 11 2 Add oil if necessary m Check compressor unloader operation 4 6 1
42. g Controller 2 6 24VDC e 8 1 PTBI 2 Em A2 112 DRI on 0 180 2 2 CBS MCS H TT ES 2 _ 2 1112 DR2 85 86 CBE 0 220 552 2 2 P FLOOR BLOWERS o des o X 2 30 87 M OL b Cu Ur L CB2 P E 1 c 1 2 307 87 24VDC OX 5 SE EES 0 E ur O 2 6 85 86 01 Way em e eum 1 SWV geg Sen Quom H ma L TBE ACFL 3 30 87 307 87 ACFL2 L emm emm WATER VALVE 7 ga L c F N CLUTCH 30 187 85 86 1 RELAY 2 MC3 CMTH COOL YELLOW lan 24 Be zk 55 J MC4 CMTH ELECTRONIC 3 4 roe CONTROL CFS MCS 7810 d Y 7 3 4 TC T HPS LPS i a sd A 85 86 03 2 2 OTO OG 1612 2 44 DAS sO 81 F Y 301 87A 85 86 Y 02 B 4 v SE 85 L i 2 N 85 86 L JB 2 Energized Circuit De en
43. ge pressure Loss of refrigerant charge Excessive system pressure in the high side of the system Table 1 2 Safety Devices Safety Device Circuit Breaker CB1 Manual Reset Circuit Breaker CB2 Manual Reset Circuit Breaker CB3 Manual Reset Circuit Breaker CB4 Manual Reset Circuit Breaker CB5 Manual Reset Circuit Breaker CB6 Manual Reset High Pressure Switch HPS Manual Reset Low Pressure Switch LPS Automatic Reset High pressure relief valve Replace 1 6 Device Setting 1 Opens at 8 amps 2 Opens at 15 amps 3 Opens at 35 amps 4 Opens at 35 amps 5 Opens at 50 amps 6 Opens at 50 amps 7 Refer to Section 1 2 8 Opens at6 psig 1 9 28kg cm 9 Opens at 450 psig 31 6 kg cm 15 SYSTEM OPERATING CONTROLS AND COMPONENTS a Temperature Controller Thermostat There are two types of controllers Cycling Clutch or Reheat With Cycling Clutch the compressor cycles on and off to control businterior temperature With R eheat the coolant valve opensor closeson thermostat command to control bus interior temperature while the air conditioning mode continues to operate b Manual Switches E vaporator Blower Speed Switch EBS The manual vaporator Blower Speed switch E BS is located next to the circuit breakers on the electrical component panel see Figure 1 3 When the EBS switch is closed the M
44. kwise manifold discharge hand valve approximately one turn 8 Tighten charging hose on to dummy fitting 9 Slowly open the manifold suction hand valve to purge line 10 Tighten suction hose at the suction service valve port 11 Frontseat close both manifold hand valves 12 Crack open suction service valve 1 4 to 1 2 turns 4 3 PUMPING THE SYSTEM DOWN REMOVING THE REFRIGERANT CHARGE NOTE To avoid damageto the earth sozone layer use a refrigerant recovery system whenever removing refrigerant 4 3 1 System Pump Down To service or replace the filter drier expansion valve evaporator coil or suction line pump the refrigerantinto condenser coil and receiver as follows a Install manifold gauge set Refer to section 4 2 b Frontseat filter drier inlet valve by turning clockwise Start unit and run A C Stop theunit when the suction pressure reaches 1 psig 0 1kg cm to maintain a slight positive pressure Frontseat close suction service valveto trap the refrigerant in the low side of the system between the compressor suction service valve and the filter drier inlet valve d Service or replace the necessary component on the low side of the system NOTES 1 Before opening up any part of the system a slight positive pressure should beindicated gauge 2 When opening up the refrigerant system certain partsmayfrost Ilow the partto warm to ambient temperature before dismantling This avoids in
45. mp from can after each use W hen the compressor isin operation the pump check valve prevents the loss of refrigerant while allowing servicemen to develop sufficient pressure to overcome the operating suction pressure to add oil as necessary Backseat suction service valve and connect oil charging hose to port Crack the service valve and purge the oil hose at oil pump Add oil as necessary 2 Closed System Method In an emergency where an oil pump is not available oil may be drawn into the compressor through the suction service valve CAUTION Extreme care must be taken to ensure the manifold connection remains immersed in oil at all times Otherwise air and moisture will be drawn into the compressor Connect the suction connection of the gauge manifold to the compressor suction service valve port and immerse the common connection of the gauge manifold in an open container of refrigeration oil Crack the suction service valve and gauge valve to vent a small amount of refrigerant through the common connection and the oil to purge the lines of air Close the gauge manifold valve With the unit running frontseat the suction service valve and pull a vacuum in the compressor crankcase SLOWLY crack the suction gauge manifold valve and oil will flow through the suction service valve into the compressor A dd oil as necessary c Adding Oil to Service Replacement Compressor NOTE For correct oil charge refer to sec
46. nd Replacing High or Low Pressure Cutout Switch 4 9 4 10 4 11 4 12 4 13 48 1 Replacing High or Low Pressure Switch 4 8 2 Checking High or Low Pressure Switch fasse ERES Thermostatic Expansion Valve 056 Compressor Maintenance 4 11 1 Removing the Compressor 4 11 2 Compressor Oil Level Servicing Pressure Actuated Compressor nloader If Equipped Electrical Compressor U nloader If Equipped 1 1 1 1 1 5 1 5 1 6 1 7 1 7 1 8 2 1 2 1 2 1 2 1 2 1 2 2 2 2 3 1 3 1 3 1 3 1 3 2 3 2 3 2 3 2 3 2 3 2 4 1 4 1 4 1 4 2 4 2 4 2 4 2 4 2 4 3 4 3 4 3 4 4 4 4 4 4 4 4 4 4 4 5 4 5 4 5 4 6 4 7 4 8 TABLE OF CONTENTS CONT D Section Page 5 ELECTRICAL SCHEMATIC WIRING DIAGRAM e Ric Mocks dE 5 1 LIST OF ILLUSTRATIONS Figure Page 1 1 Unit Assembly Back View 1 2 1 2 Unit Assembly Inside View 1 3 1 3 Electrical Component Panel Assembly 1 4 1 4 Heater Flow Cycle neutre CERE tenue 1 7 1 5 Air Conditioning Cycle tod api Ce eov epa ce rs 1 8 2 1 U nit Control Panel hte RR Rer pre ce RE RR E ai 2 1 2 2 Temperature Controller Sequence
47. on may occur 5 1 LINE SYMBOL DESCRIPTION 21 23 24 25 B BLOWER RELAYS 9 16 COOL RELAY 1 CIRCUIT BREAKER FLOOR HEATER 8 5 8 CB2 CIRCUIT BREAKER COOL amp WATER PUMP RELAY 15 AMP 2 CB3 CIRCUIT BREAKER FAN MOTOR 1 35 5 3 CB4 CIRCUIT BREAKER FAN MOTOR NO 2 35 AMPS 4 CB5 CIRCUIT BREAKER CONDENSER FAN MOTOR 1 50 AMPS 5 CB6 CIRCUIT BREAKER CONDENSER FAN MOTOR 2 50 5 19 CFS zu CONDENSER FAN SWITCH 4 5 CM CONDENSER FAN MOTOR 11 21 22 24 D DIODE 3 DRI DROPPING RESISTOR EVAP MOTORS LOW SPEED 5 DR2 DROPPING RESISTOR CONDENSER MOTORS LOW SPEED 21 5 SPEED SWITCH 2 3 Se EVAP BLOWER MOTOR 6 23 FLOOR BLOWER RELAY 20 HPS HIGH PRESSURE SWITCH 14 16 20 LOCK IN RELAY 20 LPS LOW PRESSURE SWITCH 2 22 MOTOR CONTACTOR EVAP BLOWER LOW SPEED 2 21 MC2 MOTOR CONTACTOR BLOWER HIGH SPEED 4 17 MC3 MOTOR CONTACTOR CONDENSER FAN NO 1 5 18 MC4 MOTOR CONTACTOR CONDENSER FAN NO 2 4 19 MCS MOTOR CONTACTOR CONDENSER FAN HIGH SPEED P CONNECTOR PLUG 2 PTB POWER TERMINAL BLOCK TB TERMINAL BLOCK 18 TC TEMPERATURE CONTROLLER REHEAT 17 18 21 TH Se THERMAL OVERLOAD PROTECTORS 8 10 W WATER PUMP RELAY CUSTOMER SUPPLIED COMPONENTS 14 15 ACFL A C FAULT LIGHT 21 UNIT CIRCUIT BREAKER 9 COMPRESSOR CLUTCH
48. otor Contact 2 will energize to lock in the evaporator motors in high speed Climate Control Switch CCS Supplied by The Climate Control Switch CCS activates the operation or the unit This switch is located on the driver s control panel When the Climate Control Switch is closed 24 vdc is fed from the circuit breaker CB through the CCS switch to feed power to terminal of the temperature controller Defrost Switch DEF Supplied by OEM The Defrost Switch DEF when activated will manually place the unit in defrost When the DEF switch is closed the Water Valve coil will energize and close a normally open set of contacts to feed 24 vdc to activate Water Pump WP This switch when closed during the or Vent mode will override the temperature controller heat relay to activate the water pump c Thermal Switches 5 Water Temperature Switch WTS Supplied by OEM The Water Temperature Switch WTS is located on the block of the vehicle engine and senses the vehicles engine coolant temperature The WTS is a normally closed switch that opens on temperature rise at 120 F 49 C When the vehicle water temperature is below 120 F the switch is closed completing a circuit for the Blower Relays B1 amp B2 Energizing the Blower Relays will prevent the floor blowers and evaporator blowers from activating to prevent the circulation of cooler air throughout the bus during the initial start up of the vehicle and uni
49. pen M C3 contacts to start the Condenser Fan M otor CM 1 d Motor Contactor Relay 4 Energizing the M otor Contactor Relay M C4 will close a set of normally open M C4 contacts to start Condenser Fan M otor CM 1 low speed e Motor Contactor Relay MC5 When the Condenser Fan Switch closes the M otor Contactor Relay M C5 will energizes and close a set of normally open M C5 contacats to put Condenser Fan otorsCM 1 amp CM 2in high speed Refer to section 1 2 for CFS settings f Motor Contactor Relay MC2 Energizing the M otor Contactor Relay M C2 will close a set of normally open M C2 contacats to put Evaporator Fan Motors EM 1 amp EM 2in high speed 9 Motor Contactor Relay 1 Motor Contactor Relay MC1 will be energized through a normally closed set of Blower Relay Contacts B2 Evaporator Fan Motors amp EM2 The energized M C1 relay will close a set of normally open M C1 contacts to start the E vaporator Fan otors EM 1 amp EM 2 low speed If high pressure occures in the system the High Pressure Switch H PS will cut out to open the circuit to the compressor contact to stop compressor and refrigerant flow When the compressor shuts down dueto a safety device opening the evaporator blower motors will continue to run untill the A C switch is placed in the OFF position NOTE If the unit shuts down due to high current the circuit must be manually reset by pushing the main
50. r Contactor 5 coil This will lockthe Condenser M otors CM 1 amp 2 inhigh speed until the condenser pressure drops to 250 10 psig resuming low speed operation 16 HEATER FLOW CYCLE Heating is controlled by the thermostat which controls the operation of the water solenoid valve WSV When water solenoid valve is energized the valve will open to allow engine coolant to flow through the heater coil 1 Heater Coil 5 Outlet Tube 2 Air Bleed Hose 6 Outlet Hose 3 Inlet Tube 7 Inlet Hose 4 Air Bleed Valve Figure 1 4 Heater Flow Cycle 17 AIR CONDITIONING REFRIGERANT CYCLE When air conditioning is selected the unit operates as a vapor compression system using R 22 or R 134a asa refrigerant The main components of the system are the reciprocating compressors air cooled condenser coil thermostatic expansion valve and evaporator coil The compressors raise the pressure and the temperature of the refrigerant and forces it into the condenser tubes The condenser fan circulates surrounding air which is a temperature lower than the refrigerant over the outside of the condenser tubes H eat 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
51. rature using the pressure temperature Table 4 1 or Table 4 2 e If gauge reading is 3 psig or more than the calculated P T pressure in step d noncondensibles are present f Remove refrigerant using a refrigerant recovery system g Evacuate and dehydrate the system Refer to section 4 5 h Charge the unit Refer to section 4 6 4 8 CHECKING AND REPLACING HIGH OR LOW PRESSURE CUTOUT SWITCH 4 8 1 Replacing High or Low Pressure Switch a Thehighand low pressure switches are equipped with schrader valve to allow removal and installation without pumping the unit down b Disconnect wiring from defective switch The high and low pressure switches are shown in Figure 1 1 c Install new cutout switch after verifying switch settings Refer to section 4 8 2 4 8 2 Checking High or Low Pressure Switch WARNING Do not use a nitrogen cylinder without a pressure regulator Do not use oxygen in or near a refrigeration system or as an explosion may occur a Removeswitch from unit All unitsare equipped with schrader valves at the high pressure switch connection b Connectanohmmeter acrossswitch terminals f the switch is good the ohmmeter will indicate no resistance indicating the contacts are closed Connect switch to a cylinder of dry nitrogen see Figure 4 3 d Set nitrogen pressure regulator higher than cut out point on switch being tested Refer to section 1 2 e Open cylinder valve Slowly open the r
52. receiver The receiver serves as a liquid refrigerant reservoir so that a constant supply of liquid is available to the evaporator as needed and as a storage space when pumping down the system T he receiver is equipped with a sight glassto observe the refrigerant for restricted flow and correct charge level Therefrigerantleavesthe receiver and flowsthrough the manual receiver outlet valve and through a filter drier where an absorbent keeps the refrigerant clean and dry The liquid then flows to a thermostatic expansion valve which reduces pressure and temperature of the liquid and meters the flow of liquid refrigerant to the evaporator to obtain 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 blower H eat transfer is established from the evaporator air flowing over the tubes to the refrigerant inside the tubes The evaporator tubes have aluminum fins to increase heat transfer from the air to the refrigerant therefore the cooler air is circulated to the interior of the bus 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 suction line Thelow pressure refrigerant vapor isnow drawn into the compressor where the cycle repeats
53. rminal Block 440 Watt Resistor 9 Evaporator Air Filter Evaporator Blower Wheel 10 Evaporator Coil Lower Mounting Bracket 11 24 V Interface Plug Electrical Panel See Figure 1 3 Figure 1 2 Unit Assembly Inside View 1 3 Nr Co N Floor Heater Circuit Breaker CB1 8 Amp Compressor Clutch and Water Pump Circuit Breaker CB2 15 Amp Evaporator Fan Motor No 1 Circuit Breaker CB3 35 Amp Evaporator Fan Motor No 2 Circuit Breaker CB4 35 Amp Condenser Fan Motor No 1 Circuit Breaker CB5 50 Amp Condenser Fan Motor No 2 Circuit Breaker CB6 50 Amp Evaporator Blower Speed Switch EBS Cool Relay C Lock In Relay L 10 11 12 13 14 15 16 17 18 19 20 Blower Relay No 1 B Blower Relay No 2 B2 Floor Blower Relay F Motor Contactor 1 Low Speed Diode No 4 D4 Motor Contactor 2 MC2 Evaporator Blower High Speed Motor Contactor MC3 Condenser Fan No 1 Motor Contactor 4 MC4 Condenser Fan No 2 Motor Contactor 5 MC5 Condenser Fan High Speed Heat Relay H 1 Evaporator Blower Figure 1 3 Electrical Component Panel Assembly 1 4 12 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS a Refrigeration Charge R 22 or R 134a 16 to 17 Ib b Compressor M odel 05G No of Cylinder 6 Weight Dry 145 105 66 kg including clutch Oil Charge 6 75 pints 3 2 liters Oil L e
54. sig 6 7 kg cm R 134a Units Superheat Setting 10 F 5 6 C M OP Setting 53 9 4 psig 3 8 kg cm Low Pressure Switch LPS O pens at 6 3 psig 42 2 kg cm Closes at 25 3 psig 2 8 2 kg cm 9 g High Pressure Switch HPS R 22 Units O pens at 425 10 psig 30 7 Closes at 300 10 psig 21 7 kg cm 1 5 Bearing Lubrication Factory Lubricated additional grease not required H orsepower 0 6 44 kw Full Load Amps FLA 22 amps O perating Speed 1200 rpm Voltage 24 vdc Dropping Resistor DR 1 240 watts Condenser Fan M otor Bearing Lubrication Factory Lubricated additional grease not required H orsepower 0 5 hp 37 kw Full Load Amps FLA 18 amps O perating Speed 1550 rpm Voltage 24 vdc Dropping Resistor DR 2 440 watts 14 SAFETY DEVICES System components are protected from damage caused by unsafe operating conditionswith safety devices listed in table Table 1 2 During mode operation will automatically stop when such unsafe conditions occur by de energizing the compressor clutch and condenser motor coils if the Freeze Protection Temperature Switch FPTS High Pressure Switch H PS or Low Pressure Switch LPS opens The A C fail lights ACFL16 amp 2 will illuminate to indicate an unsafe condition The evaporator blower motors will continue to run to circulate the air During the vent or heat modes operation will automatically stop if the cir
55. t Condenser M otor Thermal Protectors CMTH Each condenser motor is equipped with an internal thermal protector switch If excessive motor temperature exist the CM TH switch will open to de energize the corresponding motor contactor This will stop the effected condenser motor Evaporator M otor Thermal Protectors EM TH Each evaporator blower motor is equipped with an internal thermal protector switch If either motor 1 7 experiences excessive temperature the corresponding EMTH switch will open to de energize the motor contacts This will stop both evaporator blower motor Freeze Protection Temperature Switch FPTS The Freeze Protection Temperature Switch FPTS is located on the relay panel The sensor is located on evaporator coil The FPTS protects the coil from frost build up The switch opens when coil temperature fallsto 30 2 to de energize the Lock in Relay 1 De energizing the Lock in Relay will cause the condenser fan motors to stop and drop out the compressor clutch to stop the refrigerant cycle At this timeonlythe evaporator blower will continueto run until the coil temperature rises to 38 2 at which time the switch will close to continue operation d Pressure Switches HI Condenser Fan Switch CFS The Condenser Fan Switch CFS is located on the inlet line to the receiver next to the filter drier If the condenser coil pressure reaches 320 10 psig the CFS will close to energizes M oto
56. ternal condensation which puts moisture in the system e Leak check connections refer to section 4 4 f Evacuate and dehydrate the low side refer to section 4 5 4 3 2 Removing the Refrigerant Charge Connect a refrigerant recovery system to the unit to remove refrigerant charge R efer to instruction provided by the manufacture of the refrigerant recovery system 44 REFRIGERANT LEAK CHECK A refrigerant leak check should always be performed after the system has been opened to replace or repair a component To check for leaks in the refrigeration system perform the following procedure 4 2 l If system is without refrigerant charge system with refrigerant to build up pressure between 30 to 50 psig 2 1 to 3 5 kg cm NOTES It must be emphasized that only the correct refrigerant drum be connected to pressurize the system ny other gas vapor will contaminate the system which will require additional purging and evacuation of the high side discharge of the system 2 Check for leaks The recommended procedure for finding leaks in a system is with a halide torch or electronic leak detector Testing joints with soapsuds is satisfactory only for locating large leaks 3 Removerefrigerant using a refrigerant recovery system and repair any leaks 4 Evacuate and dehydrate the system Refer to section 4 5 5 Charge the unit Refer to section 4 6 4 5 EVACUATION AND DEHYDRATION a General M oisture isth
57. tic Wiring Diagram Model 68R M 40 504 23 5 12 5 7 Electrical Schematic Wiring Diagram M odel 68R M 40 524 11 5 14 LIST OF TABLES Table Page 1 1 Model Charte Rendement EHE 1 1 1 2 Safety Devices bue E eed m ee Sead aee 1 6 4 1 R 22 Pressure Temperature Chart 4 8 4 2 R 134a Temperature Pressure Chart 4 9 1 DESCRIPTION 1 1 INTRODUCTION Thismanual contains O peratingand Electrical D ata and Service Instructions for the RM40 Bus Air Conditioning and H eating systems shown in the model below TheRM 40 unit is a one piece system consisting of a condenser evaporator and heater coil assemblies The unit is installed in the rear A C compartment of the bus The RM 40 unit interfaces with the bus s customer supplied compressor driver s switches floor heater water valves and pump to provide a full air conditioning heating and ventilation system The RM 40 has two types of controllers Cycling Clutch or Reheat With Cycling Clutch the compressor cycles on and off to control bus interior temperature With Reheat the coolant valve opens or closes on thermostat command to control businterior temperature while the air conditioning mode continues to operate Table 1 1 M odel Chart Refrigerant TMC Option Controller Driver s Switches customer supplied
58. tion 1 2 Service replacement compressors may or may not be shipped with oil If compressor is without oil A dd oil through the suction service valve flange cavity or by removing the oil fill plug see Figure 4 6 d To Remove Oil from the Compressor 1 Ifthe oil level recorded in step a 3 above isat 3 4 of the sight glass remove 1 1 2 pints of oil from the compressor If at a full sight glass remove 2 3 4 pints of oil from the compressor 2 Close suction service valve frontseat and pump unit down to 3to 5 psig Frontseat discharge service valve and slowly bleed remaining refrigerant 3 Remove the oil drain plug on the bottom plate of the compressor and drain the proper amount of oil from the compressor R eplace the plug securely back into the compressor 4 Repeat step 1 to ensure proper oil level 412 SERVICING PRESSURE ACTUATED COMPRESSOR UNLOADER If Equipped The unloader valve settings unloads cuts out and loads cuts in are in section 1 2 Start the following procedure with the compressor not running a Connectaset of manifold pressure gaugesto the service valves or high and low pressure switch connections in order to monitor both discharge and suction pressures 4 7 b Turn large 1 1 6 in load up set point adjustment hex nut on top of unloader CW to bottom stop O n models equipped with unloader adjustment jam nut 1 1 2in turn thisnut CW to bottom stop then turn theload up adjustment he
59. to equalize at new setting 3 Replace cap and check operation of unit 4 11 056 COMPRESSOR MAINTENANCE 4 11 1 Removing the compressor If compressor is inoperative and unit still has refrigerant pressure frontseat suction and discharge service valves to trap most of the refrigerant in the unit If compressor runs pump down the unit Refer to section 4 3 a Slowly release compressor pressure b Remove bolts from suction and discharge service valve flanges c Disconnect wiring to the high and low pressure cutout switches if equipped and the clutch Identify wiring and switches if necessary d Attach slingor other device to the compressor and remove compressor from the bus e Remove the three socket head cap screws from both cylinder headsthat have the unloader valve on 05G compressor Remove the unloader valve and bypass piston assembly keeping the same capscrews with the assembly The original unloader valve must transferred to the replacement compressor The plug arrangement removed from the replacement is installed in the original compressor as a seal If piston is stuck it may be extracted by threading socket head capscrew into top of piston A small teflon seat ring at bottom of piston must be removed NOTES 1 Theservice replacement 05G compressor is sold without shutoff valves but with valve pads Theoptional unloadersare not supplied as the cylinder heads are shipped with plugs Customer should r
60. ualize or evacuate the system Low Pressure Gauge High Pressure Hand Valve Frontseated Hand Valve Open C Connection to Either Vacuum Pump Refrigerant Cylinder Oil Container Purge Line A Connection to Low Side of System B Connection to High Side of System Figure 4 1 Manifold Gauge Set The manifold gauge in Figure 4 1 shows hand valves gauges and refrigerant openings W hen the low pressure hand valve is frontseated turned all the way in the low evaporator pressure can be checked When the high pressure hand valve is frontseated high condensing pressure can be checked When both valves are open turning counter clockwise high pressure vapor will flow into the low side When the low pressure valve is open 4 1 REFERENCE SECTION 2 1 None 4 1 1 None 4 4 4 9 4 1 2 None Replace Tighten None None None the system can be charged or evacuated Oil can also be added to the system a Installing the M anifold Gauge Set 1 Remove both service valve stems and service port caps Backseat counter clockwise both service valves 2 Connect the high side hose tightly to discharge service valve port 3 Connect the low side hose loosely to suction service valve port 4 Loosen charging center hose at dummy fitting of manifold set 5 Frontseat clockwise both manifold gauge hand valves 6 Crack open discharge service valve 1 4 to 1 2 turns 7 Slowly open counter cloc
61. uence REHEAT AIR CONDITIONING High Speed Blowers VENT ONLY Low Speed Blowers HEAT Low Speed Blowers Temperature Rise AIR CONDITIONING High Speed Blowers VENT ONLY Low Speed Blowers HEAT Low Speed Blowers Temperature Fall Figure 2 3 Temperature Controller Sequence CYCLING CLUTCH 1 24VDC MC2 DR1 0 18 2 A1 5 1772 DR2 0 220 2 A1 E S FLOOR BLOWERS Ag eos PTB2 W P 2 I 24VDC ce Ten EN 1 DEF 85 0 E ae aa WSV Spi x 7813 SWV 3 CONN I L 7815 ELE D E A 11 3 4 zn 30 874 I GREEN YELLOW 5 S L VALVE A C RELAY 1 RELAY 2 2 24V i ELECTRONIC 4 CONTROL 3 I D RED B i ces 82 14 5 TT 1 30 87 SCH NI E 30 87 85 86 YD2 TB4 85 86 UM B2 85 86 Energized Circuit Figure 2 4 Air Conditioning M ode with Reheat Controller 2 4 JB 2
62. vel Old Crankcase before S N 4994 Bottom to 1 4 of sight glass New Crankcase beginning S N 4994 Between M ax marks on crankcase A pproved Compressor Oils R 22 Calumet R efining Co R 030 Texaco WF 68 Witco 4G S Suniso A pproved Compressor Oils R 134a Castrol cematic SW 68 M obil EAL Artic 68 ICI Emkarate R L 68H 05G Compressor Pressure U nloaders ptional PRESSURE UNLOADER R 134a Units O pens at 300 10 psig 21 7 Closes at 200 10 psig 14 7 Condenser Fan Switch CFS R 22 Units Closes for high speed 320 10 psig 22 5 7 kg cm O pens for Low Speed 250 10 psig 17 8 7 kg cm R 134a Units Closes for high speed 220 10 psig 15 5 7 kg cm pensfor L ow Speed 170 10 psig 12 7 kg cm 9 Freeze Protection Temperature Switch FPTS O pens at 32 2 is C Closes at 38 2 3 Water Temperature Switch WTS First Unloader Second Unloader Refrigerant Load Up Unload Load Up Unload 65 psig 55 psig 60 psig 50 psig R 134a 36 psig 30 psig 30psig 24 psig k d 05G Compressor Electric Unloaders Pressure Switches UPS1 amp UPS2 Optional UNLOADER PRESSURE SWITCH Customer Supplied Unit Weight Approximate 600 Ib 272 kg 13 ELECTRICAL SPECIFICATIONS a Evaporator H eater Blower M otor Thermostatic Expansion Valve R 22 Units Superheat Setting 12 6 7 M OP Setting 95 5 7 p
63. xnut CW down againstthejam nut Remove sealing caps unscrew CCW that cover the pressure differential adjustment screws on side of both unloader flanges d Turn unloader differential screw CW to bottom stop e Check oil level in compressor sight glass and then start engine f Runengine at fast idle for ten minutes g Slowly turn the suction service valve stem CW until the suction pressure is at the valves cut in loaded setting NOTE At this point the difference between the discharge and suction pressures also must be at least 10 to 120 psig 7 0 to 8 4kg cm It may be necessary to artificially load the system i e block off condenser coil air flow or open hot water valve to attain the required system pressures Turntheload up adjustment nut the pressure unloader slowly CCW while observing system pressures until the pressures jump i e rapid decreasein suction pressure and increase in discharge pressure The cylinder head isnow loaded L eavethe adjustment nut in this position i Readjust the suction service valve until the suction pressure isatthe valve cut out unloaded setting Turn the pressure differential adjustment screw slowly CCW until the pressures jump i e rapid increase in suction pressure and decrease in discharge pressure Thecylinder head 15 unloaded eavethe adjustment nut in this position k Thisunloader is now completely set Check for repeatability by

Bus Air Conditioning Unit - North America Transport Air Conditioning

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