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Carrier 58MVP User's Manual

1. 18 chassis ground 19 3 19 The ORANGE wire from low pressure switch LPS is shorting to ground Replace or repair it 9 20 Does Fault Code 24 occur when gas valve GV is energized 21 28 21 jumper wire across R and W W1 thermostat terminals and replace secondary voltage 22 22 Disconnect BLUE wire to gas GV and jumper R and W W1 thermostat terminals on furnace ES n 23 control board 23 Does Fault Code 34 IGNITION PROVING FAULT occur If not Fault Code 24 should occur when 27 24 E BLUE wire is energized 24 Disconnect PL1 from furnace control board 25 25 Do you have continuity between BLUE wire and chassis ground 26 3 26 The BLUE wire to gas valve GV is shorting to ground Replace or repair it 9 27 Replace gas valve GV 4 28 Add a jumper across R and W2 thermostat terminals on furnace control board 29 29 Does Fault Code 24 occur when high pressure switch HPS is energized 30 39 30 Disconnect jumper wire across R W W1 and W2 thermostat terminals and replace secondary volt u _ 31 age fuse 31 Disconnect BROWN wire to gas valve GV and jumper W W1 and W2 thermostat terminals on 26 32 furnace control board 32 Does Fault Code 24 occur when high pressure switch HPS is energized 33 27 33 Disconnect PL1 from furnace control board 34 34 Do you have continuity between B
2. COMMUNICATION CONNECTOR cag Control Center 34 115 V CONNECTORS SEE DETAILS ABOVE PRESSURE SWITCH CONNECTOR HUM HUMIDIFIER TERMINAL 24 VAC 0 5 AMP MAX 24 V THERMOSTAT TERMINALS DEHUMIDIFY ENABLE DE WHEN PROVIDED DEHUMIDIFIER DEHUM CONNECTOR 4 3 AMP FUSE VY STATUS AND DIAGNOSTIC less LED LIGHTS y AIR CONDITIONING A C SETUP SWITCH SETUP SWITCHES SW AND BLOWER OFF DELAY SETUP SWITCHES MODEL PLUG A98351 BuuiM
3. 4 Observe operation of furnace for several minutes or until fault occurs 5 5 Does fault occur again 6 EN 6 Does a different fault occur 8 T Go to page number indicated in Index for fault code flashed INDEX 8 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 9 Is collector box and inducer housing properly draining condensate 25 10 Fix problem 8 11 Are pressure switches wired correctly 10 12 Replace pressure switch assembly 8 13 Wis have 24v between C Common on low pressure switch LPS and Com on furnace control 14 E 14 The YELLOW wire to low pressure switch LPS is not making good connection Repair wire or re 8 place harness Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals Turn 15 power on and wait a few sec for self test then reconnect jumper across R W W1 and W2 thermo 16 stat terminals 16 Do you have 24v between connector terminal PL2 2 and Com on furnace control board when fault 18 _ occurs 17 Replace furnace control board 8 18 19 Do you have continuity across terminal PL2 2 and N O Normally Open contact on low pressure 19 switch LPS 20 The ORANGE wire from low pressure switch LPS to furnace control board is not making good con 20 nection or low gas pressure switch LGPS when used is open Check propane line pressure if us 10 ing LGPS
4. STEP ACTION YES NO GO TO 1 Make sure power is on ES 2 2 Remove blower access panel and depress door Switch Use a piece of tape to hold switch closed _ 3 Wait a few sec for self test before proceeding to next step 3 Make sure thermostat is calling for heat 4 4 Make sure thermostat fan control is in AUTO position if equipped 5 5 Check fuses breakers or manual disconnects to be sure they are correctly set 6 6 Does 120 v wiring match unit wiring schematic 9 7 7 Fix problem 8 8 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 9 Do you have 120 vac at primary leads P1 and P2 on furnace control board 14 10 10 Do you have 120 vac to furnace control board 11 12 11 Check all 120 vac connections at furnace control board If necessary replace furnace control board 8 12 Turn power off 13 13 Check continuity of power supply leads and door switch if wired with 120 vac 7 14 Do you 24v between SEC 1 and SEC 2 on furnace control board 19 15 15 Turn power off 16 16 Do you have continuity across door switch 17 18 17 Replace transformer If transformer fails again replace transformer and furnace control board 8 18 Replace door switch 8 19 Do you have 24v between R and Com on furnace control board 21 20 20 Replace furnace control board 8 21 Do you have 2
5. 88 ae oo at lear i E an HISH 938 afale NOL 30 J 06 0021 WBA 59 m 28 84 275 es 77 5 123135 30 12 AV IHd 330 42 05 san ijs SES HD DES 4 2 ION sna 39 QNV OV 30 ONY old dad old 8 ma Inma i035 Moss 43335 a 6 r 3 ERS pa Fab ERI _ pe 127 22 8 m 2 gt gt gt eld ILON 5 8 RU A B ul T NH NHO YINI v MS Nug SK 31ON PS ma god Aiddns i NA g M m J 75 S large rj 623 Si 001090 A 080270 3NvdOHd SVO WHNLWN H 90200 1 TORANN n 090270 n HOLIMS LOANNOOSIC 93514 INVHOVIO OLLVIN3HOS 103NNOOSIG OVA SLL OL run uo oneureuos FULM osn Mo oq UMOYS IUO SI PUN uo oneureuos FUM JT 3 LON 35 Appendix Isolation Circuits FURNACE THERMOSTAT 2 K FIELD SUPPLIED FIELD SUPPLIED A SN 24 VAC SPST RELAY 24 VAC 40VA l Og e e o TRANSFORMER P Ki ka Ki 3lE TUE I W K T UNIT I o e Wty l w La Ww i 2 l l Y
6. AIR CONDITIONER AIRFLOW SWITCH POSITION ALLOWABLE FURNACE MODEL SETUP TONS A C2 3 040 060 080 080 100 120 Default MORE CENE 1 1 2 600 ON OFF OFF X X X 2 800 OFF OFF X X X X X X 2 1 2 1000 ON ON OFF X X X X X X 3 1200 OFF OFF ON X X X X X X 3 1 2 1400 ON OFF X X X X X X 4 1600 OFF ON ON X X X 5 2000 ON X X X X Indicates allowable selection Table 3 Continuous Fan CF Airflow Setup Switch Position CONTINUOUS FAN CF SWITCH POSITION ALLOWABLE FURNACE KODEL SETUP CFM CF 1 CF 2 CF 3 040 060 080 5 Ton 100 120 Default OFF OFF OFF 565 515 690 690 860 1035 600 X X X 800 OFF ON OFF X X X X X X 1000 ON ON OFF X X X X X X 1200 OFF OFF ON X X X X X X 1400 ON OFF ON X X X X X X 1600 OFF ON ON X X X 2000 ON ON ON X X X Add 15 additional CFM when Bypass Humidifier switch SW 3 on control board is used X Indicates allowable selection Table 4 Two Speed AC HP Airflow Requirements CFM OUTDOOR UNIT CAPACITY 036 048 060 Setting 3 Tons 1200 4 Tons 1600 5 Tons 2000 CF Setting 800 1000 1000 Fault Code 24 SECONDARY VOLTAGE FUSE IS OPEN Indicates fuse is open and there is a short in low voltage wiring
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8. 215 Ton 600 800 1000 1200 1400 1600 1800 2000 CFM A97321 Air Delivery Curve 120 20 Constant System Curves 2V5 Ton 31 Ton 700 900 1100 1300 1500 1700 1900 2100 CFM A97323 Static Pressure Reading Location Diagrams COMBUSTION So eS HUMIDIFIER OUTDOOR UNIT COIL SUPPLY STATIC E INCLINE MANOMETER n RETURN STATIC oO GAS FIRED WATER HEATER ELECTRONIC AIR CLEANER INCLINE MANOMETER D gt AIRFLOW Basement Upflow Application Upflow Total Static Pressure Reading Locations ELECTRONIC AIR CLEANER S m MANOMETER A C COIL RETURN STATIC INCLINE MANOMETER qu COMBUSTION NIE RH gt AIRFLOW Closet Downflow Application SEEN Downflow Total Static Pressure Reading Locations 42 RETURN 5 6 INCLINE ELECTRONIC AIR CLEANER E T FURNACE CONDENSATE DRAIN
9. 46 47 INSTRUCTIONS This guide uses your expertise and observations to lead you to the trouble spot as efficiently as possible This is only intended as a guide and should not be used blindly Your experience and expertise are of high value when troubleshooting this unit Do not disregard all of your instincts The microprocessor furnace control was designed with diagnostic capabilities built in LEDs are used to flash a fault code which will lead you to 1 of the subsections as listed in the Index You should ALWAYS begin in the START HERE subsection see Index for page number which will guide you to the appropriate subsection where a minimal number of steps will be used to correct the problem If you are very experienced at how this furnace operates and you suspect the problem is either the blower motor inducer motor or furnace control board you can use the quick motor test procedure at the end of the troubleshooting guide to isolate the problem or direct you to appropriate section in main troubleshooting guide Once in a subsection read the statement or question A statement will have a number in the GO TO column Do whatever the statement says then proceed to step indicated in the GO TO column If the step is a question a question will have a number in the YES or NO column answer it YES or NO If the answer is YES go to step indicated in YES column If the answer is go to step indica
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11. 21 21 Check that the GREEN wire is properly connected to furnace sheet metal and clean flame sensor 4 5 withfine sandpaper Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS If problem 22 persists on an intermittent basis replace furnace control board If problem still persists on an inter INDEX mittent basis after replacing furnace control board contact your distributor Fault Code 21 INVALID MODEL SELECTION Personality connector PL5 is either not connected or jumpered wrong STEP ACTION NO GO TO 1 Turn power off and remove blower access panel 2 2 Is personality connector PL5 properly wired per furnace model size chart on wiring diagram 3 3 Replace or rewire personality connector 4 4 Go to page number indicated Index for CLEANUP AND START UP INSTRUCTIONS INDEX 5 Depress door switch Use a piece of tape to hold switch closed 6 6 Make sure thermostat is calling for heat or jumper R and W W1 thermostat terminals 7 T Will furnace operate while flashing fault code 8 8 Replace furnace control board 4 9 Are personality plug wires making good connection 11 The furnace will operate acceptably however a model selection circuit failure has occurred and fur 10 nace control board is defaulting to last valid model selection Board replacement is recommended 4 but not necessary This fault code will flash cont
12. 29 43 If possible replace inducer wheel Otherwise replace inducer motor assembly 8 44 Is there any frost build up on combustion air inlet 45 46 45 The problem is caused by reversed vent and combustion air pipes or some other moist air entering a 14 combustion air pipe You have inadequate combustion air supply This may be caused by 46 Excessive restriction in combustion air or vent pipe 14 Internal restriction in coupling box or secondary heat exchangers 4T Replace pressure switch assembly 70 48 Is unit a trophy unit 50 49 49 Does fault occur before blower motor turns ON 47 51 Replace pressure switch assembly with pressure switch assembly used in NON trophy models or 250 replace furnace control board If you replace furnace control board make sure replacement control 4 70 has a date code of 9837 or later Only replace the pressure switch assembly or the furnace control board NOT both gt 51 Replace furnace control board 70 52 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 53 53 Turn power on and wait several sec before proceeding to next step 54 54 Disconnect collector box tube to pressure switch assembly 55 55 Jumper R and W W1 thermostat terminals on furnace control board 56 56 Does Fault Code 42 occur within 1
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14. NOTE The blower starts at approximately 400 500 RPM After 20 sec the motor is turned off for 1 10 of a sec where a coast down calibration is done to evaluate resistance of the conditioned air duct system The microprocessor then determines blower RPM required to provide proper airflow for heating mode 8 Electronic Air Cleaner The EAC 1 terminal is energized whenever blower operates 9 Inducer speed reduction If cycle starts in low heat inducer speed reduces slightly after the flame sense If cycle starts in high heat inducer speed increases 15 sec after flame sense The reduction in speed in low heat is to optimize combustion for maximum efficiency 10 Call for heat terminated When the call for heat is satisfied the R W W1 signal is terminated de energizing gas valve stopping gas flow to burners and HUM terminal is de energized a R W W1 signal terminated with R Y Y2 and R G still present The blower changes its speed to cooling RPM R 24V DD DA DAD DO W2 W W1 Y Y2 SEC 1 DEHUM HEHEHE OOO Uem WITHOUT DE CONNECTION Y HUM G R 24V DDD ID DDI W2 Com WW1 Y Y2 DE CONNECTION
15. STEP ACTION NO GO TO 1 Turn power off and remove blower access panel 2 2 Is secondary voltage fuse blown Check continuity to make sure 3 3 Replace furnace control board 4 4 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 5 Disconnect all thermostat leads from furnace control board including HUM terminal and replace 6 secondary voltage fuse 6 Depress door switch Use a piece of tape to hold switch closed 7 7 Does Fault Code 24 flash 10 8 You have a short circuit in limit switch circuit This includes limit switch flame rollout switch and 9 auxiliary limit switch 9 Fix problem and replace secondary voltage fuse if necessary 4 10 Jumper and W W1 thermostat terminals on furnace control board 11 11 Does Fault Code 24 occur when is energized 16 12 jumper wire across R W W1 thermostat terminals and replace secondary voltage 13 13 Disconnect PL2 from furnace control board and jumper R and W W1 thermostat terminals on fur _ 14 nace control board 14 Does Fault Code 24 occur when is energized 15 15 You have a short circuit in pressure switch circuit 9 16 Does Fault Code 24 occur when low pressure switch is energized 20 17 Disconnect PL2 from furnace control board 18 19 Do you have continuity between the Normally Open contact on low pressure switch LPS and
16. an intermittent basis after replacing furnace control board contact your distributor SERVICE LED CODE STATUS RED LED1 ON Furnace is operating in emergency heat RED LED2 ON The microprocessor has malfunctioned To reset Put setup switch SW 1 in the ON the door switch pushed in and power to the unit ON Disconnect jumper and place setup switch in the OFF position If LED2 reappears replace main control board YELLOW LED3 Furnace is operating in high heat GREEN LED4 ON Furnace is operating in low heat RED LED2 FLASHING Line voltage polarity is reversed position and jumper thermostat terminals R W W1 and Y Y2 simultaneously with EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST DIGIT DETERMINED BY NUMBER OF FLASHES OF THE YELLOW LED AND THE SECOND DIGIT DETERMINED BY NUMBER OF FLASHES OF THE GREEN LED 11 NO FAULT IN RECENT HISTORY DISPLAY Indicates no faults have occurred within last five cycles To read recent fault history put setup switch SW 1 in the ON position To clear recent fault history put setup switch SW 1 in the ON position and jumper thermostat terminals R W W1 and Y Y2 simultaneously until an 11 is flashed 12 BLOWER CALIBRATION LOCKOUT Indicates RPM calculated for low heat was less than 250 RPM or greater than 1300 RPM on two successive attempts Auto reset after three hours Reset power and refer to fault 444 section 13 LIMIT SWITC
17. SEC mem DEUM XOT A WITH DE CONNECTION A98293 Fig 1 Variable Speed Furnace Control b R W W1 with R Y Y2 and signals terminated The blower continues to operate completing a normal blower off delay 11 Post purge The inducer continues operating for 15 sec after gas valve is de energized Step 7 Continuous Fan Mode 1 Operating with continuous fan only a Call for continuous fan The thermostat closes R G circuit b Blower on The blower starts immediately NOTE The blower starts at approximately 400 500 RPM After 20 sec the motor is turned off for 1 10 of a sec where a coast down calibration is done to evaluate resistance of the conditioned air duct system The microprocessor then determines blower RPM required to provide proper airflow for heating mode NOTE The continuous fan speed is the same as low heat speed unless it is field adjusted to another desired airflow See Continu ous Fan Setup Switches section in Installation Start Up and Operating Instructions for details There is also a chart on schematic diagram shown in Appendix A c Electronic Air Cleaner The EAC 1 terminal is ener gized whenever blower operates regardless of operating mode 2 Operating with continuous fan R G and call for heat R W W1 is received
18. AIR CONDITIONING REFRIGERATION COIL PIPING E AIRFLOW Attic Horizontal Application INCLINE MANOMETER A95092 Horizontal Right and Left Airflow Total Static Pressure Reading Locations Example 1 Example 2 Return ESP after filter 0 40 in wc Return ESP before filter Supply ESP before coil 0 55 in wc Filter Static Drop 2000 Total ESP 0 95 in wc Supply ESP after coil Coil Static Drop Wet Total ESP Tools Needed 1 Pitot Tube 1 Incline Manometer Magnahelic Both examples are correct Example 1 ESP readings were taken as laid out in Static Pressure Reading Location Diagrams Example 2 readings are taken as described The coil and filter static pressure drops were taken from the manufacturer s Product Data Sheets with the assumption that we are trying to deliver 2000 CFM this will vary NOTE By plotting total ESP of 0 95 in wc on the air delivery curve of a 100 000 Btuh input furnace a Fault Code 44 would flash See Example Air Delivery Curve 43 Duct Static Check Sheet Furnace Model Number Serial Number Position U F D F H R H L Outdoor Unit Model Number Serial Number What type of media filter is being used What is static pressure drop across filter Indoor Coil Model Number Serial Number Thermostat Electronic Air Cleaner At what CFM Does fault code go away when you remove filter What Zone System is applied What Zone has highest total ESP Is a Zone By
19. ig a A io i al an Td lo ik E lot p d p M n NDS M io 12 Ki FIELD SUPPLIED K2 24 SPST RELAYS BOARD A95097 A95098 Fig 5 Isolation of W W1 and 2 Fig 6 Isolation of Outdoor Unit with a Separate Thermostat Circuits 24 v Supply Appendix C Pressure Check Diagram 0 4 IN SLOPE GAGE A95050 HIGH PRESSURE SWITCH LOW PRESSURE SWITCH Make Point Break Point Make Point Break Point 40 000 1 81 in wc max 1 63 in wc 0 05 0 75 in wc max 0 60 in wc 0 05 UNIT SIZE BTUH 60 000 80 000 100 000 120 000 1 81 in wc max 1 63 in wc 0 05 0 95 in wc max 0 80 in wc 0 05 Appendix D Quick Motor Test Procedure In an effort to provide a method of troubleshooting inducer and blower motor by themselves the following procedure may save you some time in the event any of the following fault codes are the reason for service call 12 32 41 42 or 44 If you get any other fault code you should use main troubleshooting guide to isolate problem STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and disconnect R thermostat lead 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 Put setup switch SW 6 for COMPONENT TEST in ON position 4 After COMPONENT TEST is completed does Fault Code 11 flash 5 8 5 Turn power off put
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21. y o Carrier HEATING amp COOLING 58MVP Variable Speed 2 Stage Electronic Condensing Furnace Visit www carrier com Troubleshooting Guide NOTE Read the entire instruction manual before starting the installation SAFETY CONSIDERATIONS INDEX PAGE Instructions e ore P DU e en UE ET Re es 1 Example ER 2 Sequence of Operation 1 5 Self Test ee eite reete e ens ee 2 Heating Mode annee 2 Heating Mode Two 22 2 Emergency Heat 22 3 Cooling Mode 3 Heat Pump 3 4 Continuous Fan 4 Component Test err erobern rere 4 5 Bypass Humidifier Mode eene 5 Dehumidification Mode serere 5 Zone Modes trt teret eee dede 5 Start eoo p e i aes 6 Service Label Fault Code Instructions sss 7 8 Improper Operation With No Flashing Fault Code 9 Not Enough Cooling Airflow see 10 High Fire Temperature Rise Too Low Cold Blow 11 LEDs 1 2 3 4 On 5 2222 11 12 RED LED2 Flashing 12 Fault Code 11 No Fault in Recent History Display 13 Fault Code 12 Blower Calibration Lockout 13 1
22. LOW 10 2 11 2 vdc State 3 HIGH 8 4 9 4 vdc Connect a DC voltmeter across terminals PL1 6 BROWN and PL1 5 ORANGE on furnace control board Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON 25 Does voltage across BROWN and ORANGE wires change between states as shown below State 1 OFF 11 5 12 5 vdc State 2 LOW 10 2 11 2 vdc State 3 HIGH 8 4 9 4 vdc 26 You have an open wire or bad terminal on ORANGE wire between connectors PL1 and PL7 Repair it or replace main harness 27 Does Fault Code 41 flash 28 7 28 Does blower motor MTR2 turn on and come up to speed 48 29 29 Remove tape from door switch and turn power off at main disconnect 30 AJOJN 19 21 23 22 22 26 37 30 Does blower wheel rub against blower housing 16 31 31 Does blower wheel turn freely 32 33 32 Is blower wheel firmly mounted on motor shaft 34 16 Replace blower motor or blower control module attached to the blower motor If you replace the 33 blower control module go to step 51 Always inspect failed motor for water damage If present find 16 source of water and fix Check A coil and or humidifier 34 Put setup switch SW 6 for COMPONENT TEST in OFF position 35 35 Turn power on and depress do
23. This fault indicates that inducer motor is not operating at calculated RPM or has not started within 10 sec after a call for heat STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and disconnect all thermostat leads from furnace con e 2 trol board 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Jumper R and W W1 thermostat terminals on furnace control board 4 4 Observe operation of furnace for next 8 minutes or until fault occurs 5 5 Does fault occur again 9 6 6 Does a different fault occur 7 60 T Go to page number indicated in Index for fault code flashed INDEX 8 Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS INDEX 9 Does fault occur within 11 sec after a call for heat 52 35 10 Do you have 120v between I1 and I2 on furnace control board 11 14 11 Do you have 120v between terminals PL7 6 and PL7 12 13 12 12 You have an open wire or bad terminal on either the BLACK or WHITE wire between furnace con _ 14 trol board and inducer motor MTR1 13 Are all pins and wire leads intact on connectors between furnace control board and inducer motor 15 14 14 Fix problem E 8 15 Turn power off and disconnect jumper wire across R and W W1 thermostat te
24. 29 23 29 Is inducer blower wheel okay 31 30 30 If possible replace inducer blower wheel Otherwise replace inducer motor assembly 10 31 Is there any frost build up on combustion air inlet 32 33 32 The problem is caused by reversed vent and combustion air pipes or some other moist air entering d wy 27 combustion air pipe 33 You have excessive restriction in combustion air or vent pipe 10 34 The problem is either a sag in vent pipe or a clogged drain trap or line 27 35 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 36 36 Turn power on and wait several sec then jumper R and W W1 thermostat terminals on furnace con 37 trol board 37 Do you have 24v between connector terminal PL2 2 and Com on furnace control board when fault 13 38 occurs 38 Turn power off 39 Do you have continuity across terminal PL2 2 and N O Normally Open contact on low pressure 39 16 40 switch LPS The ORANGE wire from low pressure switch LPS to furnace control board is not making good con 40 nection or low gas pressure switch LGPS when used is open Check propane line pressure if us 27 ing LGPS otherwise repair wire or replace harness 41 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 42 42 Connect 1 side of a slope manometer with a tee to collector box p
25. OUTSIDE VALID LOWIHEAE SPEED RANGE COMPONENT TEST To initiate the component test sequence shut OFF the room thermostat or disconnect the R thermostat lead Put setup switch SW 6 in the ON position to start the component test seouence Once initiated the main board will turn ON the inducer motor low speed inducer motor high speed hot surface ignitor blower motor low speed and blower motor high speed for 15 20 seconds each When component test is completed one or more of the following codes will flash Gas Valve and Humidifier will not be turned on CODE DESCRIPTION 11 Indicates inducer and blower motor tested OK Visual check of hot surface ignitor required 22 SETUP ERROR Same as code 22 above 41 BLOWER OUTSIDE VALID SPEED RANGE Indicates blower motor failed test Check blower wiring and control center 42 INDUCER OUTSIDE VALID SPEED RANGE Indicates inducer motor failed test Check inducer wiring and control center To repeat component test turn setup switch SW 6 OFF and then back ON After component test is completed put setup switch SW 6 in the OFF position and reconnect thermostat lead 320624 101 REV J 99243 A99243b Fig 4 Service Label Fault Code Instructions 8 IMPROPER OPERATION WITH FLASHING FAULT CODE Generally this indicates there is power to furnace control board
26. When setup switch SW 3 BPH is in ON position RPM calculated for low heat is multiplied by 1 15 for all furnace model sizes This compensates for increased return air temperature caused by by passed air supply VARIABLE SPEED THERMIDISTAT CONDENSING FURNACE 24 VACHOT 446 AS DEHUM DEHUMIDIFY DHUM Pano 74 24 COMM C Fig 2 Without DE Connection 98294 Step 10 Dehumidification Mode dehumidification input is provided via a 1 4 in male quick connect terminal labeled DEHUM located next to the transformer secondary connections The DEHUM input acts differently de pending on which style of variable speed furnace control you have The older style variable speed furnace control shown in Fig 1 DOES NOT have a DE connection while the newer style variable speed furnace control shown in Fig 1 has a DE connection The newer style variable speed furnace control is expected to be available by mid 1998 Both of these variable speed furnace controls function the same except the DEHUM logic is reversed This logic reversal has come about from historical use of a standard humidistat to do dehumidification since the contacts open on high humidity thus removing the 24 v signal to initiate dehumidification On the older style variable speed furnace controls a fiel
27. at low heat speed or reduces to low heat speed for selected off delay On propane installations when low gas pressure switch LGPS is open due to switch failure low propane line pressure CALL FOR HEAT TIf low pressure switch LPS is made when a call for heat is initiated furnace control board flashes Fault Code 32 until switch opens then cycle begins LOW HEAT 1 PREPURGE If low pressure switch LPS does not make within 45 sec after call for heat is initiated furnace control board starts flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle If low pressure switch LPS opens before ignition furnace control board starts flashing Fault Code 32 and ramps inducer RPM up until low pressure switch LPS remakes When low pressure switch LPS remakes furnace control board stops flashing Fault Code 32 and continues heating cycle If low pressure switch LPS does not remake within 45 sec after opening furnace control board continues flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle 2 STEADY STATE If low pressure switch LPS opens during low heat furnace control board starts flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle HIGH HEAT 1 PREPURGE f low pressure switch LPS does not make within 45 sec after call for heat is initiated furnace c
28. change in amperage SPECIAL NOTE ALL VOLTMETERS ARE NOT THE SAME YOUR VOLTAGE READINGS WILL VARY THIS APPLIES TO THE ENTIRE CONTENT OF THIS TROUBLESHOOTING MANUAL 45 Appendix G Thermostat Staging Algorithm Unit Default Algorithm is initiated with Low Heat for 16 minutes If call for heat still exists unit transfers into High Heat until thermostat is satisfied Low Heat run time is calculated based on previous heating cycle High Heat on time is not calculated High Heat is energized 1 of 3 ways and runs until thermostat has been satisfied 1 After Low Heat has run for 16 minutes and call for heat is still present 2 When algorithm does its calculation of previous cycle and determines High Heat is necessary 3 After the amount of calculated Low Heat on time has elapsed and there is still a call for heat present The following flowchart shows how the algorithm calculates low heat on times To use calculations the amount of time unit ran in Low Heat LH and High Heat HH during previous cycle must be known The algorithm uses these values to decide which stage of heat should be initiated on next call for heat Four examples also follow illustrating what the unit will do on a cold start coming out of night setback coming on in low fire and coming on in high fire EXAMPLE 1 Furnace ran for 16 minutes in Low Heat and 5 minutes in High Heat LH 16 5 Calculate 228 X 16 350 X 5 5398 3648 lt 5
29. control board 5 Connect a DC voltmeter across ORANGE and VIOLET wires at connector PL13 then repeat 17 the COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Do you see ap 18 19 proximately the same DC voltages across ORANGE and VIOLET wires that you saw in Step 15 Replace entire blower motor or blower control module attached to the blower motor If you replace 418 the blower control module go to step 44 Always inspect failed motor for water damage If present 4 find source of water and fix Check A coil and or humidifier 13 You have an open wire or bad terminal on either the ORANGE or VIOLET wire between connectors 13 PL13 and PL3 Repair it or replace blower harness es m 20 Remove tape from door switch and turn power off at main disconnect 21 21 Does blower wheel rub against blower housing 4 22 22 Does blower wheel turn freely 23 Is blower wheel firmly mounted on motor shaft 25 4 Replace entire blower motor or blower control module attached to the blower motor If you replace 24 the blower control module go to step 44 Always inspect failed motor for water damage If present 4 find source of water and fix Check A coil and or humidifier 25 Disconnect jumper wire across R and W W1 thermostat terminals 26 26 Turn power back on Depress door switch Use a piece of tape to hold sw
30. damaged 531 Remove two 1 4 in hex head bolts from blower control module attached to blower motor DO NOT 32 REMOVE TORX HEAD SCREWS located next to 1 4 in hex head bolts Carefully lift blower control module off blower motor Depress latch on internal connector to discon 32 nect blower control module from motor portion of blower motor DO NOT PULL ON WIRES GRIP 33 PLUG ONLY When blower control module is completely detached from blower motor verify with standard ohm meter that the resistance from each motor lead in motor plug to unpainted motor end plate is 533 greater than 100k ohms Then verify motor windings are not shorted or open by measuring resis _ 34 tance between each combination of pins motor plug there are three different combinations pin 1 2 pin 2 3 and pin 1 3 Resis tance should be approxi mately equal across each combination of pins 34 Did the motor pass the resistance check 35 37 35 Does blower wheel turn freely with blower control module removed 36 37 536 Replace blower control module Inspect failed blower control module for water damage If present ES E 10 find source of water and fix Check A coil and or humidifier 237 Replace entire blower motor including blower control module Inspect blower control module wa ns Ho 10 i ter damage If present find source of water and fix Check A coil and or humidifier 28 Fault Code 42 INDUCER OUTSIDE VALID SPEED RANGE
31. for service purposes Failure to follow this warning could result in personal injury or death When items 1 5 been completed the following will occur 1 The control center goes through a brief self test This self test takes approximately 2 sec to complete After door switch is closed red microprocessor LED briefly comes on Then green LED comes on for 1 sec followed by 1 sec where both green and yellow LEDs are on During this time the micro processor is checking itself 2 Inducer motor operates for 20 sec at low speed operates 20 sec at high speed then turns off 3 Hot surface ignitor is energized for 15 sec then de energized 4 Main blower motor operates for 20 sec at low speed operates for 20 sec at high speed then turns off 5 After component operation test is completed 1 or more fault codes 11 22 41 or 42 will flash See service label on back of main furnace door or Fig 1 for explanation of fault codes NOTE To repeat component test turn setup switch SW 6 to OFF and then back to ON After component test perform the following 1 Release blower panel access door switch and turn setup switch SW 6 to OFF position 2 If applicable replace blower access panel and check LED status by removing plug in blower access panel 3 Reinstall main furnace door if all LEDs are off indicating furnace is ready to operate when a signal from thermostat is received Step 9 Bypass Humidifier Mode
32. from room thermostat Observe each cycle for 20 minutes or until a fault code is flashed If a fault occurs refer to the Index Recycle as necessary and check thermostat heat anticipator setting gas input rates and temperature rises These proce dures are outlined in Installation Start Up and Operating Instructions Check operation of safety devices pressure switches limit switch and flame roll out switch 33 Put setup switch SW 1 in ON position and jumper W W1 and Y Y2 terminals on furnace control board simultaneously to clear fault history Put setup switch SW 1 in OFF position Put all setup switches in their proper positions Remove tape from the door switch Replace thermostat leads if necessary Set thermostat in AUTO position calling for heat Set thermostat to desired temperature Replace blower access panel and main furnace door Clean up SURFACE IGNITOR CONNECTOR EAC ELECTRONIC AIR CLEANER TERMINALS 115 VAC 1 AMP MAX MAIN HARNESS CONNECTOR MAIN BLOWER CONTROL WIRE CONNECTOR TRANSFORMER 24 V CONNECTORS SEC 2 SEC 1 CONTINUOUS FAN CF SETUP SWITCHES Appendix A Board Layout and Schematic EEEEEEEEDEE
33. selected on the A C setup switches Airflow will be reduced to 340 or 315 CFM per ton depending on board style See Fig 1 when a dehumidification demand exists See Air Conditioning Setup Switches section in Installation Start Up and Operating Instructions for details There is also a chart on schematic in Appendix A NOTE If Y Y2 thermostat lead is not connected to furnace control center blower motor operates in continuous fan speed and indoor coil freeze up may occur 3 Electronic Air Cleaner The EAC 1 terminal is energized whenever blower operates 4 Cooling unit The cooling unit stops when thermostat R Y signal is terminated 5 Blower off delay When thermostat is satisfied the R Y Y2 and R G signals are terminated and blower remains operating for 90 sec On newer style control boards See Fig 1 the blower airflow will drop by 21 percent during the off delay period when the DE jumper is connected The DE jumper is only removed to enable the DEHUM input for use with a thermidistat or humidistat for dehumidification purposes Step 6 Heat Pump Mode When furnace is operating in heat pump heating mode R Y Y2 and R G circuits are closed energizing heat pump and blower operates at cooling speed When heat pump defrost is required R W W1 circuits close starting gas heat cycle and blower adjusts to low heat speed 1 Prepurge period The inducer motor is turned on and slowly comes up to speed When low pressure s
34. setup switch SW 6 for COMPONENT TEST in OFF position and reconnect R thermostat lead to furnace control board Replace blower access panel and turn power on Wait a few sec then reset thermostat Observe operation of furnace through 1 heating cycle 6 T Go to page number indicated in Index for START HERE section INDEX 8 Does Fault Code 42 flash 9 27 9 Does inducer motor MTR1 turn on and come up to speed 24 10 10 Does inducer wheel rub against inducer housing 16 11 11 Does inducer wheel turn freely 12 19 12 Do you have 120v between I1 and I2 on furnace control board 13 16 13 Do you have 120v between terminals PL7 6 PL7 12 15 14 14 You have an open wire or bad terminal on either the BLACK or WHITE wire between furnace con 16 trol board and inducer motor MTR1 15 Are all pins and wire leads intact on connectors between furnace control board and inducer motor 18 16 16 Fix problem 17 17 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX Check Inducer PW line To do this connect a DC voltmeter across terminals PL7 2 BROWN and PL7 10 YELLOW on inducer motor Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across PL7 2 PL7 10 change between states as 18 shown below 19 20 x State 1 0 1 0 1 vdc State 2 LOW 2 0 3 0 vdc State 3 HIGH 7 0 8 0 vdc 19 Repla
35. wire across R and W W1 thermostat terminals 22 22 PL10 PL13 for possible intermittent connection of ORANGE and VIO _ 23 27 23 Are ORANGE and VIOLET wires from PL3 PL13 making good contact 24 17 Replace entire blower motor or blower control module attached to the blower motor If you replace 24 MN 17 the blower control module go to step 26 Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS If problem 525 persists on an intermittent basis replace entire blower motor or blower control module attached to INDEX the blower motor If your replace the blower control module go to step 26 If problem still persists on an intermittent basis after replacing blower motor contact your distributor WARNING Wait at least 5 minutes after disconnecting line voltage from equipment before opening blower motor to prevent electric shock which can cause personal injury or death 26 Remove tape from door switch and turn power off at main disconnect 27 27 Disconnect PL10 from blower assembly e 28 28 Remove control box assembly from blower shelf and position out of the way 29 29 Remove blower assembly from furnace 30 2530 Disconnect both multi pin connectors from blower control module attached to the blower motor _ 31 sure to depress release latches on connectors or they may get
36. 1 sec after a call for heat 57 58 57 Reconnect collector box tube to pressure switch assembly 10 58 Reconnect collector box tube to pressure switch assembly 36 Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS If problem 59 ed INDEX persists on an intermittent basis contact your distributor 60 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 61 61 Turn power on and wait several sec then jumper R W W1 and W2 thermostat terminals on fur 2 lt 62 nace control board Does fault occur a few sec after high pressure switch HPS makes 62 NOTE Check for 24v between the N O Normally Open contact on high pressure switch 63 67 HPS and Com on furnace control board to know when high pressure switch HPS makes 63 Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals 64 64 Connect 1 side of a slope manometer with a tee to collector box pressure tap Connect other side M 65 with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix C 65 Turn power on and wait several sec then jumper R W W1 and W2 thermostat terminals on fur E 66 nace control board Do you have more than 1 9 in wc pressure drop across heat exchangers when high pressure 66 switch HPS makes 47 44 NOTE Check for 24v between the N O Normally Open contact on high pressure switch HPS and C
37. 398 5 2600 calculate next cycle Low Heat run time 1 6 therefore during next cycle unit will run for 2 minutes in Low Heat and then switch High Heat if a call for heat is still present EXAMPLE 2 Furnace ran for 16 minutes in Low Heat and 10 minutes in High Heat LH 16 HH 10 Calculate 228 X 16 350 X 10 7148 7148 gt 5600 therefore next cycle will be initiated in High Heat Low Heat run time is 0 minutes EXAMPLE 3 Furnace ran for 13 minutes in Low Heat LH and 5 minutes in High Heat HH This will happen if control algorithm calculated maximum Low Heat run time be 13 minutes based on a previous cycle LH 13 HH 5 Calculate 228 X 13 350 X 5 4714 3648 4714 5 2500 Fy therefore calculate the next cycle Low Heat run time LH un time 122 7 26 therefore unit will run for 7 minutes in Low Heat and then switch to High Heat if a call for heat is still present EXAMPLE 4 Furnace ran for 0 minutes in Low Heat and 10 minutes in High Heat LH 0 HH 10 Calculate 228 X 0 350 X 10 3500 3500 lt 3648 therefore next cycle will be initiated in Low Heat up to 16 minutes maximum then switch to High Heat if a call for heat is still present 46 v60S6V p ysyes s jejsouueu se eq 2 0 S14 JO 5 uni ui L 0099 reay 10
38. 4v between W W1 and Com on furnace control board 24 22 22 Check to see that thermostat is calling for heat 23 23 You have a defective thermostat or a break in the wiring between thermostat and furnace 7 24 Does furnace respond to the call for heat 27 25 25 Turn power off 26 26 Press down on microprocessor chip and make sure it is properly seated to furnace control board If d 7 it is replace furnace control board Does furnace keep repeating the following cycle Inducer motor MTR1 runs inducer motor MTR1 27 Stops furnace control board goes through self test sequence blower motor runs for 1 minute and 28 34 then cycle repeats 28 Disconnect BROWN wire to gas valve GV 29 29 Does furnace still alternately cycle inducer motor go through a self test and then run blower motor 30 37 21 as described in Step 27 30 Disconnect humidifier lead from HUM terminal on furnace control board 31 31 Does furnace still alternately cycle inducer motor go through a self test and then run blower motor 33 32 as described in Step 27 32 There is a direct short in wiring to humidifier solenoid coil or short is inside humidifier solenoid coil 7 33 There is a direct short in either the pressure Switch circuits gas valve GV or wiring to gas valve eM 7 GV If hot surface ignitor comes on during the cycle short is in gas valve or wiring to gas valve 34 Does furnace ever abruptly shut down
39. 5 Fault Code 13 Limit Switch Lockout 15 16 Fault Code 14 Ignition Lockout een 17 Fault Code 21 Invalid Model Selection x Fault Code 22 Set Up Error eese 18 Fault Code 23 Invalid Blower Airflow Selection 18 Fault Code 24 Secondary Voltage Fuse Is Open 19 20 Fault Code 31 High Pressure Switch Fault 21 22 Fault Code 32 Low Pressure Switch Fault 23 24 Fault Code 33 Limit Switch Fault s 24 25 Fault Code 34 Ignition Proving Fault 26 27 Fault Code 41 Blower Outside Valid Speed Range 27 28 Fault Code 42 Inducer Outside Valid Speed 29 30 Fault Code 43 Pressure Switch Calibration Fault 30 31 Fault Code 44 Blower Calibration 32 Cleanup and Start Up Instructions 33 APPENDIX A Board Layout amp Wiring Schematic 34 35 APPENDIX B Isolation Circuits eene APPENDIX C Pressure Check Diagram APPENDIX D Quick Motor Test Procedure APPENDIX E Variable Speed Condensing Furnace Duct Static and Blower 40 44 APPENDIX F Quick Reference Information 45 APPENDIX G Thermostat Staging Algorithm
40. 6 46 Excessive restriction of airflow during locked in high fire mode caused lockout 47 Relieve restriction Check all dampers filters and return air grilles for blockage Put setup switch 4 SW iin OFF position c Ros 42 48 Fix problem 9 49 Is temperature rise within 10 of midpoint of rise range 51 41 50 Is temperature rise within 10 F of midpoint of rise range 51 16 51 Turn power off and install a temperature probe in front of limit switch button 52 Turn power on and cycle unit Does limit switch open at a temperature at least 10 F below tempera 52 ture setpoint for limit switch EXAMPLE The setpoint is 220 F but switch opens at a temperature 7 53 below 210 F 53 The problem may be related ot poor air distribution Add turning varies more supply air openings _ 48 or more return air openings Use Appendix E to evaluate 16 Fault Code 14 IGNITION LOCKOUT This fault indicates the system failed to ignite gas and prove flame in 4 attempts Control will auto reset in 3 hr This fault could also indicate the gas valve relay GVR on furnace control board is stuck closed or there is a miswire short to gas valve wiring STEP ACTION YES NO GO TO 1 power off and set thermostat to OFF position Turn power back on and wait a few sec for self 2 test before proceeding to next step 2 Does Fa
41. 9 20 Fault Code 31 HIGH PRESSURE SWITCH FAULT This fault can occur under the scenarios shown below keep in mind that whenever furnace control board shuts unit down gas shuts off immediately inducer continues running for 15 sec and if blower is running it remains running at low heat speed or reduces to low heat speed for selected off delay CALL FOR HEAT TIf high pressure switch HPS is made when a call for heat is initiated furnace control board flashes Fault Code 31 until switch opens then cycle begins LOW HEAT 1 PREPURGE AND FIRST 45 SEC AFTER IGNITION TIf high pressure switch HPS makes during prepurge or just after ignition furnace control board continues operating until burners are lit and inducer RPM is within 10 of calculated low fire RPM If high pressure switch HPS remains made furnace control board starts flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle 2 STEADY STATE TIf high pressure switch HPS makes during low heat furnace control board starts flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle HIGH HEAT 1 PREPURGE TIf high pressure switch HPS does not make within 45 sec after low pressure switch LPS makes furnace control board starts flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle If high pressure sw
42. ANGE wires change between states as shown below 23 32 State 1 OFF 11 5 12 5 vdc State 2 LOW 10 2 11 2 State 3 HIGH 8 4 9 4 vdc 32 Turn power off 33 33 Do you have continuity between PL7 1 and PL1 5 22 34 34 You have an open wire or bad terminal on ORANGE wire between connectors PL7 PL1 14 Does fault occur a few sec after low pressure switch LPS makes 35 NOTE Check for 24v between the N O Normally Open contact on low pressure switch LPS 36 48 and Com on furnace control board to know when low pressure switch LPS makes 36 Is inducer motor rotating in direction shown on inducer housing 37 22 37 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 38 38 Connect 1 side of a slope manometer with a tee to collector box pressure tap Connect other side y 39 with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix C 39 and several sec then jumper R and W W1 thermostat leads on furnace control 40 oard Do you have more than 1 0 in wc pressure drop 0 80 in wc on trophy unit across heat exchang 40 ers when low pressure switch LPS makes 47 41 NOTE Check for 24v between the Normally Open contact on low pressure switch LPS and Com on furnace control board to know when low pressure switch LPS makes 41 Turn power off 42 42 Is inducer blower wheel okay 44 43
43. COMPONENT TEST in OFF position 21 21 Jumper R W W1 thermostat terminals on furnace control board 22 22 Connect an AC voltmeter across BLUE and GREEN wires to gas valve GV Does gas valve GV re 26 23 ceive 24v 23 Turn power off 24 Do you have continuity across the following connections 24 PL1 2 and BLUE wire at gas valve GV 17 25 PL1 7 and GREEN wire at gas valve GV 25 The BLUE or GREEN wire from furnace control board to gas valve GV is not making good connec s 12 tion Repair wire s or replace harness 26 Does gas valve open and allow gas to flow 28 27 m 27 Are all manual gas cocks in ON position 11 19 28 Do main burners ignite 30 29 Check for the following 29 Inadequate flame carryover or rough ignition 19 Low inlet gas pressure 30 Do main burners stay on 40 31 31 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 32 32 Connect a DC microammeter in series with flame sensor wire 33 Turn power on and wait several sec then jumper R and W W1 thermostat terminals on furnace con 33 trol board 4 34 Is DC current below 0 5 microamps 36 35 35 Check connections and recheck current If current is near typical value and control will not stay on 42 replace furnace control board 36 Pind flame sensor with fine sandpaper and recheck current Current is typically 4 0 to 6 0 micro E E 37 37 Is c
44. Does voltage across RED and 42 BLUE wires change between states as shown below 43 41 State 1 0 1 0 1 vdc State 2 ON 9 0 10 0 vdc 43 Put setup switch SW 6 for COMPONENT TEST in OFF position X 44 Check Blower PW line To do this connect DC voltmeter across terminals PL3 1 RED and PL3 4 YELLOW on furnace control board then put setup switch SW 6 for COMPONENT TEST in ON position Does voltage across RED and YELLOW wires change between states as shown 44 below 46 45 State 1 0 1 0 1 vdc State 2 LOW 2 5 3 0 vdc State 3 HIGH 7 0 7 5 vdc Disconnect PL3 from furnace control board and connect a DC voltmeter across terminals PL3 1 and PL3 4 on furnace control board Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across PL3 1 and PL3 4 change between states as shown 45 below 33 22 State 1 0 1 0 1 vdc State 2 LOW 3 0 4 0 vdc State 3 HIGH 9 0 10 0 vdc Connect a DC voltmeter across RED and YELLOW wires at connector PL13 Repeat COM PONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across RED 46 and YELLOW wires change between states as shown below 33 47 _ 3 State 1 0 1 0 1 State 2 LOW 2 5 3 0 vdc State 3 HIGH 7 0 7 5 vdc 47 You have an open wire or bad terminal on either the RED or YELLOW wire between conne
45. ED LED turn back ON 7 31 31 Install isolation relays in the W W1 and Y Y2 circuits per Fig 5 in Appendix B or replace thermostat 8 32 Was RED LED2 ON before you started Step 1 34 33 33 eee LEDS indicates furnace is in high fire and solid GREEN LED4 indicates furnace is in m 8 w Check outdoor unit contactor Failure to pull in can cause excessive current draw on low voltage 34 circuit This can be intermittent and may require extended operation to repeat problem Isolating 35 outdoor unit may solve problem See Fig 6 in Appendix B Check thermostat wire gage between furnace and outdoor unit It is recommended that AWG No 35 18 color coded copper thermostat wire be used for lengths up to 100 ft For wire lengths over 100 14 ft use AWG No 16 wire 36 Observe operation of furnace through a 20 minute heat cycle Try to pinpoint where in cycle RED EE 37 turns ON Go to step indicated below if RED LED2 turns ON when 1 of the following events occur When gas valve is energized EX 38 37 When HSI is energized 39 When high pressure switch HPS makes during transition from low to high fire 38 RED LED2 never turns ON 40 38 Replace gas valve 8 39 Isolate humidifier with a separate 24 vac supply or replace humidifier solenoid coil 14 40 Observe operation of furnace through a 4 minute cooling cycle Does RED LED2 turn ON 41 47 41 D
46. EX 10 Put setup switch SW 2 in ON position 11 11 Jumper and W W1 thermostat terminals on furnace control board 12 12 Is furnace considerably overfired 1096 or more Clock input rate Do not use manifold pressure 14 ER method unless using propane Ensure gas inlet pressure and burner orifices natural or propane are correct Then adjust gas 13 valve to proper rate per Installation Start Up and Operating Instructions If it cannot be adjusted to 9 proper rate replace gas valve 14 Is the personality connector PL5 properly wired per furnace model sizing chart in upper left hand 15 corner of wiring schematic 15 Replace or rewire personality connector 9 15 16 Does the installation have a bypass humidifier 17 30 17 Is setup switch SW 3 in ON position 19 18 18 Put setup switch SW 3 in ON position 9 19 Cycle furnace with blower access panel in place and record temperature rise across furnace 6 min 20 utes after main burner ignition 20 Disconnect jumper wire across R and W W1 thermostat terminals and wait until blower stops 21 21 Remove blower access panel and put setup switch SW 3 in OFF position 22 22 Cycle furnace with blower access panel in place and record temperature rise across furnace 6 min m 23 utes after main burner ignition 23 Is the tem
47. H LOCKOUT Indicates the occurrence of 10 successive limit trips during high heat or three successive limit trips during low heat Auto reset after three hours Improper misaligned limit and or limit shield Improper high or low heat gas input adjustment Stuck high heat solenoid in gas valve 14 IGNITION LOCKOUT Control will auto reset after three hours Refer to 34 21 INVALID MODEL SELECTION Indicates model plug is missing or incorrect See wiring diagram for correct connector jumper location 22 SETUP ERROR Indicates setup switch SW 1 or SW 6 is positioned improperly The following combinations will cause the fault Thermostat call with SW 1 ON Thermostat call with SW 6 ON SW 1 and SW 6 both ON together 23 INVALID BLOWER AIRFLOW SELECTION Indicates improper A C or CF switch setting The 042 and 14 units can deliver 1 1 2 to 3 1 2 tons A C and 600 to 1400 CFM for continuous fan The 060 and 20 unit can deliver 2 to 5 tons and 800 to 2000 continuous fan If code is flashing unit will default to closest allowable airflow 24 SECONDARY VOLTAGE FUSE IS OPEN Check for Short circuit in secondary voltage 24V wiring 31 HIGH PRESSURE SWITCH FAULT Indicates high pressure switch is closed at call or in low heat or fails to close after call or opens in high heat Check for Plugged condensate drain Water in vent piping possibly sagging pipe Improper p
48. N YES NO GO TO 1 Turn power off and remove blower access panel Make sure thermostat is NOT calling for heat 2 2 Depress door switch Use a piece of tape to hold switch closed Wait a few sec for self test before _ 3 proceeding to next step 3 Set thermostat to call for heat or jumper R and W W1 thermostat terminals 4 4 When GREEN is ON solid clock low fire gas rate You have 16 minutes on this first call for 5 heat On propane installations check manifold pressure When YELLOW LEDS is ON solid clock high fire gas rate On propane installations check manifold _ 6 6 Is high fire rate approximately same as low fire rate 7 11 7 d have 24 vac across gas valve terminal HI and Com on furnace control board during high 10 8 mu 8 wire or bad terminal on BROWN wire from furnace control board to gas valve c zm 9 GV Repair it or replace the harness 9 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 10 Replace gas valve 9 11 Is high fire rate within 296 of that specified on rating plate 13 12 12 Ensure gas inlet pressure and burner orifices are correct then adjust gas valve to proper rate If it 9 cannot be adjusted to proper rate replace gas valve 13 Check outdoor condensing unit for operation during heating cycle 14 Check temperature rise with blower door in place Temperature rise sho
49. ROWN wire and chassis ground 35 36 35 The BROWN wire to gas valve GV is shorting to ground Replace or repair it 9 36 Disconnect PL2 from furnace control board 37 37 Do you have continuity between the N O Normally Open contact on high pressure switch HPS 38 3 and chassis ground 38 The BROWN wire from high pressure switch HPS is shorting to ground Replace or repair it 9 39 Disconnect jumper wire across W W1 and W2 thermostat terminals and wait until blower stops 40 40 Jumper and 2 thermostat terminals on furnace control board 41 41 Does Fault Code 24 occur when G and Y Y2 are energized 3 42 42 Reconnect all thermostat leads except HUM terminal if used to furnace control board and operate 43 furnace in heating and cooling mode from thermostat 43 Does Fault Code 24 occur during heating cycle 44 45 44 You have a defective thermostat or a short circuit in wiring between thermostat and furnace 9 45 Does Fault Code 24 occur during cooling cycle 46 47 46 You have a defective thermostat or a short circuit in wiring between thermostat and outdoor unit 9 47 Does problem usually occur cooling mode 48 49 48 Check outdoor unit contactor Failure to pull in can cause excessive current draw on low voltage m 9 circuit This can be an intermittent problem 49 Reconnect humidifier and check for excessive current draw
50. ST by turning setup switch SW 6 ON Does voltage across PL7 2 and PL7 10 change between states as 52 shown below 26 13 State 1 OFF 0 1 0 1 State 2 LOW 6 0 7 0 vdc State 3 HIGH 10 5 11 5 53 Make sure wire gage between main fuse box and furnace complies with wire size specification in ug 27 Installation Start Up and Operating Instructions 54 Does the fault occur before ignition 45 sec after call for heat 50 41 55 Check propane line pressure if using low gas pressure switch LGPS otherwise go to step 41 27 Fault Code 33 LIMIT SWITCH FAULT This fault indicates the limit switch rollout switch or auxiliary limit switch is open or unit is operating in high heat only mode due to 2 successive low heat limit trips STEP ACTION GO TO 1 Turn power off remove blower access panel and disconnect R thermostat lead 2 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Is the fault code flashing 4 Set thermostat to call for heat or jumper R and W W1 thermostat terminals 5 5 Observe operation of furnace for next 25 minutes 6 6 Does fault occur again 7 Does different fault occur 8 Go to page number indicated in Index for fault code flashed INDEX 24 9 Go to page num
51. Same as heat pump mode except blower on delay is 10 sec less than the heat mode After call for heat R W W1 is terminated the blower remains operat ing at low heat speed for selected blower off delay before resuming continuous fan speed 3 Operating with continuous fan R G and call for cooling R Y Y2 is received See Cooling Mode section After call for cooling R Y Y2 is terminated the blower remains operating at cooling speed for 90 sec before resuming con tinuous fan speed Step 8 Component Test components are functionally operated except gas valve with component test feature This feature helps diagnose a system problem in case of a component failure NOTE Setup switch SW 1 MUST be in OFF position or Fault Code 22 setup error will occur NOTE NO thermostat signal may be present at control center and all blower time delay off periods must be completed To initiate component test feature proceed with the following 1 Leave 115 v power to furnace turned on 2 Remove main furnace door 3 Remove blower access panel 4 Turn setup switch SW 6 to ON position 2 Manually close blower access panel door switch WARNING On some models blower access panel door switch opens only 24 v power to control center No component operation can occur The 115 v power is still present at control center transformer inducer motor and main blower motor Caution must be taken when manually closing this switch
52. Training plus hands on the products in our labs can mean increased confidence that really pays dividends in faster troubleshooting fewer callbacks Course descriptions and schedules are in our catalog CALL FOR FREE CATALOG 1 800 962 9212 Packaged Service Training Classroom Service Training A94328 Copyright 1999 CARRIER Corp 7310 W Morris St Indianapolis IN 46231 58mvp8sm C ee Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations 500 M PC 101 Catalog No 535 754 Printed in U S A Form 58MVP 8SM Pg 48 9 99 Replaces 58MVP 6SM al a 8
53. a sag in vent pipe or a clogged drain trap or line 17 33 Does fault occur before main burners ignite 34 51 34 Do you have 24v between C Common on high pressure switch HPS and Com on furnace control 36 35 board 35 d YELLOW wire to high pressure switch HPS is not making good connection Repair or replace 8 It Do you have at least 1 90 in wc pressure drop across heat exchangers when fault occurs Deter 36 mine this by connecting 1 side of slope manometer with a tee to collector box pressure tap Con 45 37 nect other side with a tee to gas valve air pressure fitting Refer to pressure check diagram in Ap pendix C 37 Is inducer motor 1 rotating in direction indicated on inducer housing 39 38 38 Replace inducer motor or inducer motor assembly 8 39 Turn power off ER 40 40 Is inducer wheel okay 42 41 41 If possible replace inducer wheel Otherwise replace inducer motor assembly 8 42 Is there any frost build up on combustion air inlet 43 44 43 The problem is caused by reversed vent and combustion air pipes or some other moist air entering 17 combustion air pipe 44 You have excessive restriction in combustion air or vent pipe 8 45 Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals 46 46 power and wait several sec then jumper W W1 W2 thermostat terminals on fur 2 47 nace
54. an start in either high or low heat If a high heat cycle is initiated the inducer continues increasing its speed after low pressure switch closes When high pressure switch closes inducer motor RPM is noted by microprocessor before the 25 sec prepurge period begins The RPM is used to evaluate vent system resistance This evaluation is then used to determine required RPM necessary to operate inducer in high heat mode 2 Humidifier HUM The HUM terminal is energized when ever the inducer prepurge period is completed 3 Ignitor warm up At end of prepurge period the hot surface ignitor HSI is energized for a 17 sec HSI warm up period 4 Ignition sequence After HSI ignitor warm up period is completed the gas valve opens permitting gas flow to burners where it is ignited After 5 sec the HSI is de energized and a 2 sec flame sensing period begins NOTE The initial heat mode after 115 v or 24 v power interrup tion will be LOW HEAT Low heat remains energized for 16 minutes before high heat is initiated providing thermostat is still calling for heat After the initial cycle the microprocessor evaluates the length of low and high heat operating times and calculates optimum length of low and high heat for next heat cycle This accommodates the heat load requirement seen as a result of thermostat operating time See Appendix G for details on thermostat staging algorithm 5 Flame sensing When burner flame is sensed the con
55. ans ON continuously 4 8 4 Go to page number indicated in Index for LEDs 1 2 3 or 4 ON SOLID INDEX 5 Is RED LED2 flashing 6 7 6 Go to page number indicated in Index for RED LED2 FLASHING INDEX 7 Go to page number indicated Index for subsection covering fault code being flashed INDEX 8 Is power on DO NOT cycle power to unit 10 9 9 Turn power on 20 Remove blower access panel and depress door switch Use a piece of tape to hold switch closed 10 Wait a few sec for self test before proceeding to next step E 1 11 Does problem appear to be low cooling airflow 12 13 12 Go to page number indicated in Index for subsection covering NOT ENOUGH COOLING AIRFLOW m INDEX 13 Make sure thermostat is calling for heat 14 14 Make sure thermostat fan control is in AUTO position if equipped 15 15 Observe operation of furnace for 20 minutes or until fault occurs 16 16 Does a fault occur 7 17 17 Is temperature rise below range specified on rating plate when unit is running in high fire 18 19 18 Go to page number indicated in Index for subsection e INDEX covering HIGH FIRE TEMPERATURE RISE TOO LOW COLD BLOW 19 Does furnace operate properly 31 28 20 Remove blower access panel and depress door Switch Use a piece of tape to hold switch closed 21 Wait a few sec for self test before proceeding to next step 21 Disconnect R ther
56. ates in high heat 7 Flame sensing When burner flame is sensed control center holds gas valve open If burner flame is not sensed control center de energizes gas valve and ignition sequence is re peated NOTE Ignition sequence repeats 3 additional times before lock out occurs Lockout automatically resets after 3 hr or can be manually reset by turning 115 v or 24 v power off not at thermostat for 3 sec minimum then turning on again Fault codes will not flash in emergency heat mode 8 Blower off delay When thermostat is satisfied the R W W1 signal is terminated de energizing gas valve stopping gas flow to burners and HUM terminal is de energized In addition blower stops immediately 9 Post purge Post purge does NOT occur The inducer stops immediately Step 5 Cooling Mode When thermostat calls for cooling the R G and R Y Y2 circuits close 1 Cooling unit The cooling unit starts when thermostat R Y signal is received 2 Blower on The control center starts blower immediately when it receives an R Y Y2 and R G signal The blower starts at approximately 400 500 RPM After 20 sec the blower is turned off for 1 10 of a sec where a coast down calibration is done to evaluate resistance of the conditioned air duct system The microprocessor then determines blower RPM required to provide selected cooling airflow NOTE In cooling mode the microprocessor adjusts blower RPM to operate at 400 CFM per ton as
57. aults have occurred in the last 5 previous cycles and setup switch SW 1 is in ON position The fault history can be cleared by jumpering W W1 and Y Y2 thermostat leads simultaneously while setup switch SW 1 is in ON position Component test was successfully completed and setup switch SW 6 is in ON position STEP ACTION NO GO TO 1 Remove blower access panel and depress door switch Use a piece of tape to hold switch closed 2 2 Is setup switch SW 1 in ON position 5 3 Put setup switch SW 1 in OFF position 4 4 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 5 Is setup switch SW 6 in ON position 7 6 Put setup switch SW 6 in OFF position 4 7 Jiggle setup switches SW 1 and SW 6 back and forth If Fault Code 11 continues to flash replace E 4 furnace control board Fault Code 12 BLOWER CALIBRATION LOCKOUT This fault indicates that blower motor speed calculated for low heat is either less than 250 RPM or greater than 1300 RPM on 2 successive attempts at calibration Control will auto reset in 3 hours STEP ACTION YES NO GO TO Turn power off wait 30 sec and then restore power Reset thermostat Observe operation of fur 1 nace through 1 heating cycle E 2 NOTE Blower access panel must be in place 2 Does only Fault Code 44 flash 40 6 3 The problem is excessive restriction in t
58. ber indicated Index for CLEANUP AND START UP INSTRUCTIONS INDEX 10 Consider this fault like a Fault Code 13 and go to page number indicated in Index for Fault Code _ _ INDEX 4 13 11 Do you have 24v between terminals PL1 9 and C 13 12 12 Replace furnace control board mE 9 13 Do you have 24v between terminals PL1 11 and C 12 15 14 You have an open RED wire or bad terminal in limit circuit Repair or replace it 9 15 Turn power off 16 16 Do you have continuity across limit switch LS 20 17 17 Wait for unit to cool then recheck for continuity across limit switch LS 18 18 Do you have continuity across limit switch LS 20 19 19 Replace limit switch m 9 20 Do you have continuity across flame rollout switch FRS 28 21 21 Can flame rollout switch FRS be reset 23 22 22 Replace flame rollout switch m 9 23 flame rollout switch FRS turn power and observe furnace operation for 2 15 minute e EN 24 y 24 Does flame rollout switch trip again 26 25 25 Does a different fault occur 8 9 You have inadequate combustion air supply This be caused by Reversed vent and combustion air pipes 26 Poor burner manifold or orifice alignment 27 Leak somewhere between primary and secondary heat exchangers Leak in secondary heat exchanger Internal restriction in coupling box or secondary heat exchanger 27 Fix problem 9 28 Do you have co
59. bligations 1 4 101 Tab 6a 8a Catalog No 535 754 Printed in U S A Form 58MVP 8SM Pg 1 9 99 Replaces 58MVP 6SM EXAMPLE Start Here Section ACTION Step 1 tells us to record status of LEDs 1 4 and go to Step 2 Step 2 asks the question Are any LEDs flashing If low pressure switch was defective a low pressure switch fault code would be flashing so the answer is YES We go to Step 5 Step 5 asks the question Is RED LED2 flashing If low pressure switch was defective low pressure switch fault code would be flashing so the answer is NO We go to Step 7 Step 1 Self Test Mode The control center goes through a brief self test whenever 115 v or 24 v power is interrupted The self test takes approximately 2 sec to complete After power is restored red microprocessor LED briefly comes on Then green LED comes on for 1 sec followed by 1 sec where both yellow and green LEDs are on During this time the microprocessor is checking itself Step 2 Heating Mode When thermostat calls for heat R W W1 circuit closes 1 Prepurge period The inducer motor is turned on and slowly comes up to speed When low pressure switch closes inducer motor RPM is noted by microprocessor and a 25 sec prepurge period begins The RPM is used to evaluate vent system resistance This evaluation is then used to determine required RPM necessary to operate inducer in low heat mode NOTE The heat cycle c
60. ce inducer motor or inducer motor assembly Inspect electronics portion of failed motor for water damage If present find source of water and fix Check A coil and or humidifier Disconnect PL7 from inducer motor and connect a DC voltmeter across terminals PL7 2 BROWN and PL7 10 YELLOW Repeat COMPONENT TEST by turning setup switch SW 6 OFF and 20 then back ON Does voltage across PL7 2 and PL7 10 change between states as shown below State 1 OFF 0 1 0 1 State 2 LOW 6 0 7 0 vdc State 3 HIGH 10 5 11 5 Connect a DC voltmeter across terminals PL1 6 BROWN and PL1 4 YELLOW on furnace control board Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON 21 Does voltage across PL1 6 and PL1 4 change between states as shown below State 1 OFF 0 1 0 1 vdc State 2 LOW 6 0 7 0 vdc State 3 HIGH 10 5 11 5 vdc 22 Replace furnace control board 17 23 You have an open wire or bad terminal on either the BROWN or YELLOW wire between connectors PL1 and PL7 Repair or replace main harness Check RPM feedback line To do this connect a DC voltmeter across terminals PL7 2 BROWN and PL7 1 ORANGE on inducer motor Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across BROWN and ORANGE wires change between 24 states as shown below 25 19 State 1 OFF 11 5 12 5 vdc State 2
61. control board 47 24v between connector terminal PL2 4 and Com on furnace control board when fault 11 48 48 Turn power off 49 Do you have continuity across terminal 2 4 Normally Open contact on high pressure 49 switch HPS mall san E 50 The BROWN wire from high pressure switch HPS to furnace control board is not making good con m 8 nection Repair wire or replace harness 51 Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals 52 52 Connect 1 side of a slope manometer with a tee to collector box pressure tap Connect other side 53 with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix C 53 Turn power on and wait several sec then jumper R W W1 and W2 thermostat terminals on fur 54 nace control board 54 Monitor slope manometer Does pressure reading appear to be stable when fault occurs 55 56 Replace pressure switch assembly If problem persists check wiring for an intermittent connection m in high pressure switch HPS circuit 56 Check for a sag vent pipe If problem persists replace inducer motor 8 22 Fault Code 32 LOW PRESSURE SWITCH FAULT This fault can occur under the scenarios shown below Keep in mind that whenever the furnace control board shuts unit down gas shuts off immediately inducer continues running for 15 sec and if blower is running it remains running
62. ctors 17 PL13 and PL3 Repair it or replace blower harness es Check RPM feedback line To do this connect a DC voltmeter across terminals PL3 2 ORANGE and PL3 3 VIOLET Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across ORANGE and VIOLET wires change between states as shown be 48 low 22 49 State 1 OFF 12 0 12 5 vdc State 2 LOW 10 7 11 7 vdc State 3 HIGH 9 7 10 7 vdc Connect a DC voltmeter across ORANGE and VIOLET wires at connector PL13 Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Does voltage across 49 ORANGE and VIOLET wires change between states as shown below 50 33 _ State 1 12 0 12 5 State 2 LOW 10 7 11 7 State 3 HIGH 9 7 10 7 vdc 50 You have an open wire or bad terminal on either the ORANGE or VIOLET wire between connectors e 17 PL13 and PL3 Repair it or replace blower harness es 38 WARNING Wait at least 5 minutes after disconnecting line voltage from equipment before opening blower motor to prevent electric shock which can cause personal injury or death ter damage If present find source of water and fix Check A coil and or humidifier 39 51 Remove tape from door switch and turn power off at main disconnect 52 52 Disconnect PL10 from blower assembly 53 853 Remove co
63. d supplied relay is required between the thermidistat or humidistat control and furnace The relay coil is connected between DHUM output on the thermidistat control and Cow terminal on the furnace control or the humidistat output and terminal on the furnace control Its normally closed contact is connected between R and DEHUM terminals on the furnace control See Fig 1 and Fig 2 When a dehumidify demand exists relay is de energized and normally closed contacts supply 24 v to the furnace DEHUM terminal As a result the furnace control reduces the blower airflow by 15 percent to 340 CFM per ton during continuous fan or cooling operation On newer style variable speed furnace controls a field supplied relay IS NOT required The DEHUM output on the thermidistat control or the humidistat output is connected directly to the DEHUM terminal on the furnace control In addition the DE jumper located next to the DEHUM terminal must be removed to enable the DEHUM input See Fig 1 and Fig 3 When a dehumidify demand exists the furnace control reduces the blower airflow by 21 percent to 315 CFM per ton during continuous fan or cooling operation VARIABLE SPEED THERMIDISTAT CONDENSING FURNACE 24 R DEHUMIDIFY DHUM L DEHUM DE NOTE 1 NOTE 1 Remove DE Connection To Enable DEHUM Input A98295 Fig 3 With DE Co
64. de energized furnace control board starts flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and disconnect R thermostat lead 2 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Jumper and W W1 thermostat terminals on furnace control board X 4 4 Observe operation of furnace through 1 heating cycle 5 5 Does fault occur again 9 6 6 Does a different fault occur 7 8 T Go to page number indicated in Index for fault code flashed INDEX 8 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 9 Does fault occur within 5 sec after W W1 is energized 10 18 10 Do you have 24v between the N O Normally Open contact on high pressure switch HPS and Com 12 15 on furnace control board 11 Replace furnace control board 8 12 Is high pressure switch HPS wired correctly 14 13 13 Rewire high pressure switch HPS per wiring diagram 8 14 Replace pressure switch assembly 8 15 Do you have 24v between connector terminal PL2 4 and Com on furnace control board 16 11 16 The main harness is miswired 17 17 Fix problem ER 8 18 Does fault occur during blower on delay period 19 23 19 Turn p
65. defective thermostat or a break in wiring between thermostat and furnace or the 2 E 6 i thermostat terminal is not wired to thermostat 6 Fix problem 7 7 Go to page number indicated Index for CLEANUP AND START UP INSTRUCTIONS INDEX 8 select switches set to proper tonnage as required by condensing unit See 10 9 9 Set air conditioning select switches A C for proper tonnage as required by condensing unit See _ 7 Table 1 10 Disconnect thermostat lead or jumper if used 11 11 Does blower motor turn off in 90 sec when G thermostat lead is disconnected 12 13 12 Replace furnace control board 7 13 Observe operation of furnace in cooling mode for 8 minutes 14 14 Does furnace operate properly in cooling mode 15 16 Make sure outdoor unit is properly charged If it is go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS If problem persists on an intermittent basis replace 13 furnace control board If problem still persists after replacing furnace control board contact your dis i nes tributor 16 Does furnace abruptly go through a self test sequence as blower comes up to speed 17 24 17 Do you have less than 17 vac between R and Com on furnace control board 18 24 18 Do you have less than 90 vac between P1 and P2 on furnace control board 19 20 19 Make sure the wire gage betwee
66. e is a 100 000 Btuh input with a 5 ton blower cooling capacity We measured total external static pressure ESP to be 0 4 in wc in low heat operation EXAMPLE AIR DELIVERY CURVE 060100 External Static Pressure in wc 215 Ton 900 1100 1300 1500 1700 1900 2100 CFM A98451 Use the dashed lines as guide lines As you can see the 0 4 in wc total ESP is in the shaded area The unit can deliver low heat but as you follow the dashed guide lines you see that they do not cross the high heat line until it is off the chart somewhere above 1 0 in wc The furnaces are rated at 0 5 in wc total ESP and are tested to 0 8 in wc total ESP See Static Pressure Reading Location Diagrams later in this Appendix for proper static reading locations When checking total ESP you must have blower operation without a Fault Code 44 occurring If you have a Fault Code 44 in cooling and your setting is at 5 tons set A C tonnage to 4 tons and see if the Fault Code 44 goes away If it does not set switches to 3 tons and so on until the Fault Code 44 goes away NOTE When adjusting airflow you must either turn power off or terminate thermostat call after every airflow adjustment Record all static readings on Duct Static Check Sheet Solutions 1 Dirty filter 2 Plugged evaporator coil 3 Re size ductwork and or layout SPECIAL NOTE In zoning applications it is recommended that when zone controls are applied duct sys
67. epair or replace blower harness es 34 Put setup switch SW 6 for COMPONENT TEST in OFF position ES m 35 Check blower PW line To do this connect a DC voltmeter across terminals PL3 1 RED and PL3 4 YELLOW then put setup switch SW 6 for COMPONENT TEST in ON position Does volt 35 age across the RED and YELLOW wires change between states as shown below 37 36 n State 1 0 1 0 1 vdc State 2 LOW 2 5 3 0 vdc State 3 HIGH 7 0 7 5 vdc Disconnect PL3 from furnace control board and connect a DC voltmeter across terminals PL3 1 and PL3 4 on furnace control board then repeat COMPONENT TEST by turning setup switch 36 SW 6 OFF and then back ON Does voltage across PL3 1 and PL3 4 change as shown below 18 16 State 1 0 1 0 1 vdc State 2 LOW 3 0 4 0 vdc State 3 HIGH 9 0 10 0 vdc Connect DC voltmeter across RED and YELLOW wires at connector PL13 then repeat 37 COMPONENT TEST by turning setup switch SW 6 OFF and then back ON Do you see approxi 18 38 mately the same DC voltages across RED and YELLOW wires that you saw in Step 35 38 You have an open wire or bad terminal on either the RED or YELLOW wire between connectors ES 5 i PL13 and PL3 Repair it or replace blower harness es Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS If problem 39 persists on an intermittent basis replace blower motor If problem still per
68. er wire across and W W1 thermostat ter minals and reset the power Reconnect jumper wire across R and W W1 thermostat terminals and 36 monitor manifold gas pressure while observing furnace operation for 10 minutes 37 NOTE Blower access panel must in place 37 Does a Fault Code 33 flash 39 38 The problem is cause by the modulating zone damper system Install a 2 stage thermostat and let 38 the zone system modulate gas flow If you still have a problem check the zone manufacturer s in 9 stallation and Troubleshooting Guide for corrective action 39 While monitoring manifold pressure in Step 36 did it drop to low fire manifold pressure during low 49 40 _ fire operation 40 Replace gas valve 9 Replace blower motor and belly band 41 NOTE Torque belly band screw to 80 in lb 6 7 ft Ib 9 WARNING DO NOT OVERTIGHTEN 42 Jumper W W1 and W2 thermostat terminals on furnace control board 43 43 Is furnace considerably overfired 1096 or more Clock input rate Do not use manifold pressure 44 45 __ method unless using propane Ensure gas inlet pressure and burner orifices natural or propane are correct Then adjust gas 44 valve to proper rate per the Installation Start Up and Operating Instructions If it cannot be ad 9 justed to proper rate replace gas valve 45 Disconnect jumper wire across W W1 and W2 thermostat terminals and wait until blower stops
69. erating 90 135 180 or 225 sec depend ing on blower off time selection The furnace is factory set for a 90 sec blower off delay 10 Post purge The inducer continues operating for 15 sec after gas valve is de energized Step 3 Heating Mode Two Stage The control center provides 2 stage heating using a single stage thermostat The control center maximizes comfort while optimiz ing efficiency to meet the demands of the conditioned area when a thermostat R W W1 signal is received If thermostat control over furnace staging is desired a 2 stage thermostat can be used When control center receives a thermostat R W W1 and R W2 signal high heat is energized and when R W W1 signal is received low heat is energized This method overrides microprocessor control of high or low heat NOTE When using 2 stage thermostat operation with R W W1 and R W2 signals setup switch SW 2 MUST be in ON position The heat cycle operates as stated in Heating Mode section To allow for greater comfort a 2 stage thermostat control is recommended when zone systems are used Step 4 Emergency Heat Mode NOTE The furnace should not be operated in emergency heat mode for extended periods of time Operation is only recom mended to provide heat until replacement components can be obtained or fault resolved In this mode the microprocessor is bypassed and the motors operate at full speed with high heat operation The heat exchang ers motors a
70. he air delivery system Check filters and ductwork Use Ap 4 pendix E to evaluate 4 Fix problem 5 5 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 6 Does Fault Code 44 flash twice followed by Fault Code 41 9 7 7 Does a different fault occur 8 39 m 8 Go to page number indicated in Index for fault code flashed INDEX 9 Turn power off and remove blower access panel 10 10 Are all pins and wire leads intact on connectors between furnace control board and blower motor 11 4 11 Depress door switch Use a piece of tape to hold switch closed Wait a few sec for self test before _ 12 proceeding to next step 12 er all thermostat leads from furnace control board and jumper R and W W1 thermostat ter Es 13 2 13 Does blower motor turn on and come up to speed 400 500 RPM before fault code flashes 20 14 Disconnect jumper wire across R and W W1 thermostat terminals turn power off and then restore 15 power Wait a few sec for self test before proceeding to next step Check RPM feedback line To do this connect a DC voltmeter across terminals PL3 2 ORANGE PL3 3 VIOLET then put setup switch SW 6 for COMPONENT TEST in ON position Does 15 voltage across ORANGE and VIOLET wires change between states as shown below 16 17 e State 1 OFF 12 0 12 5 vdc e State 2 LOW 10 7 11 7 vdc e State 3 HIGH 9 7 10 7 vdc 16 Replace furnace
71. ill allow unit to run in high fire when necessary See descrip tion of operation at start of Fault Code 44 If problem still persists use Appendix E to evaluate 10 Fix problem 7 Turn power off wait 30 sec then restore power Reset thermostat Observe operation of furnace 11 through 1 cooling cycle 12 NOTE Blower access panel must in place 12 Does Fault Code 44 occur 13 14 You have excessive restriction in air delivery system Check filter s and ductwork Furnace blower 13 will operate in cooling mode at default speed Check outdoor unit suction pressure and verify 10 charge to determine if indoor airflow is sufficient If not refer to Appendix E to evaluate Turn power off wait 30 sec then restore power Reset thermostat Observe operation of furnace 14 after it goes into high fire 15 NOTE Blower access panel must be in place 15 Does unit operate in high fire while flashing Fault Code 44 16 7 You have excessive restriction in air delivery system Check filter s and ductwork Furnace blower 16 will operate in high fire speed at 1200 RPM Check temperature rise of furnace and make sure unit 10 does not trip primary limit If it does refer to Appendix E to evaluate 32 CLEANUP AND START UP INSTRUCTIONS 1 Start furnace using procedure outlined on Lighting Instruc tions attached to furnace Observe operation of furnace through at least 1 complete heating cycle controlled
72. in low fire during a call for heat Control will auto reset in 3 hr NOTE After 2 low fire limit trips the control is locked into high heat mode however a third low heat cycle can be forced due to excessive restriction in air delivery system NOTE Boards with date codes of 9506 or later will lock into high heat mode after 2 low fire limit trips and CANNOT be forced into a third low heat cycle Therefore units with these boards can only lock out if the limit switch trips 10 times in a row in high fire during a call for heat STEP ACTION NO GO TO 1 Turn power off and remove blower access panel Disconnect all thermostat leads from furnace con 2 trol board 2 Depress door switch Use a piece of tape to hold switch closed 3 Put setup switch SW 1 in ON position 4 Is a Fault Code 44 present in the fault history 4 NOTE Read fault codes until they repeat The last fault code that occurred will flash first fol 5 lowed by the lowest number fault code EXAMPLE 13 13 44 5 Put setup switch SW 1 in OFF position 42 6 Does furnace have proper limit switch limit shield blower baffle if used and rear air baffle if 48 _ used If so are limit switch limit shield and heat exchangers properly aligned T Replace limit switch 9 8 Replace furnace control board 9 9 Go to page number indicated Index for CLEANUP AND START UP INSTRUCTIONS IND
73. inuously 11 Fix poor terminal connection or replace personality connector 4 17 Fault Code 22 SETUP ERROR This fault indicates that setup switches SW 1 or SW 6 are ON when they should be OFF The following combinations will cause the fault Thermostat call with SW 1 ON Thermostat call with SW 6 ON e SW 1 and SW 6 both ON together STEP ACTION GO TO 1 Turn power off and remove blower access panel 2 2 Make sure thermostat is NOT calling for heating or cooling Disconnect all thermostat terminal leads 3 to make sure 3 Is setup switch SW 1 in ON position 4 Put setup switch SW 1 in OFF position 5 5 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 6 Is setup switch SW 6 in ON position 7 Put setup switch SW 6 in OFF position 5 8 Replace furnace control board 5 Fault Code 23 INVALID BLOWER AIRFLOW SELECTION This fault indicates improper or CF switch setting The 14 units can deliver sufficient airflow for 1 1 2 to 3 1 2 tons A C and 600 to 1400 CFM for continuous fan The 20 unit can deliver sufficient airflow for 2 to 5 tons A C and 800 to 2000 CFM for continuous fan If fault code is flashing unit still operates but it defaults to closest allowable airflow NOTE Boards with date codes of 9506 or later will flash fault code and set continuous fan airflow to same airflow as A C if continuous fan is adjusted to a highe
74. isconnect all thermostat leads from furnace control board 42 42 Put setup switch SW 1 in ON position and jumper R W W1 and Y Y2 thermostat terminals simulta a A 43 neously until RED LED2 turns OFF 43 Put setup switch SW 1 back in OFF position 44 44 Reconnect only outdoor unit to 2 Com terminals on furnace control board 45 45 Jumper R and Y Y2 thermostat terminals 46 46 Does RED LED2 turn back ON 34 31 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS If problem 47 persists on an intermittent basis replace furnace control board If problem still persists on an inter INDEX mittent basis after replacing furnace control board contact your distributor RED LED2 FLASHING Indicates line voltage polarity is reversed STEP ACTION GO TO 1 Turn power off remove blower access panel and disconnect all thermostat leads from furnace con 2 trol board 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Is RED LED2 flashing 4 Replace furnace control board date code 9405 or later 5 5 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 6 Do you have 120 vac across L2 and chassis ground 7 Line voltage polarity is reversed Fix problem 5 8 Replace furnace control board 5 12 Fault Code 11 NO FAULT IN RECENT HISTORY DISPLAY This indicates 1 of the following No f
75. itch HPS opens before ignition furnace control board starts flashing Fault Code 31 and ramps inducer RPM up until high pressure switch HPS remakes When high pressure switch HPS remakes furnace control board stops flashing Fault Code 31 and continues heating cycle If high pressure switch HPS does not remake within 45 sec after opening furnace control board continues flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle 2 FIRST MINUTE AFTER IGNITION TIf high pressure switch HPS opens during first minute after ignition furnace control board starts flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle 3 STEADY STATE TIf high pressure switch HPS opens during high heat furnace control board starts flashing Fault Code 31 and ramps inducer RPM up until high pressure switch HPS remakes When high pressure switch HPS remakes furnace control board stops flashing Fault Code 31 and continues heating cycle If high pressure switch HPS does not remake within 45 sec after opening furnace control board continues flashing Fault Code 31 shuts unit down waits 2 minutes stops flashing Fault Code 31 and restarts heating cycle 4 HIGH FIRE TO LOW FIRE TRANSITION When using 2 stage thermostat and W2 is de energized high pressure switch HPS must open within 45 sec If high pressure switch HPS does not open within 45 sec after W2 was
76. itch closed Wait a few 27 sec for self test before proceeding to next step 27 Do you have 120v between B1 and B2 on furnace control board 28 4 28 Do you have 120v between BLACK and WHITE power leads at blower motor MTR2 30 29 29 You have an open wire or bad terminal on either the BLACK or WHITE wire between furnace con E 5 trol board and blower motor MTR2 Check blower ON OFF line To do this connect a DC voltmeter across terminals PL3 1 RED and PL3 5 BLUE then put setup switch SW 6 for COMPONENT TEST in ON position Does 30 voltage across RED and BLUE wires change between states as shown below 32 31 State 1 0 1 0 1 vdc State 2 ON 9 0 10 0 vdc Disconnect PL3 from furnace control board and connect a DC voltmeter across terminals PL3 1 and PL3 5 on furnace control board then repeat COMPONENT TEST by turning setup switch 31 SW 6 OFF and then back ON Does voltage across 3 1 PL3 5 change between states as 18 16 a shown below State 1 0 1 0 1 vdc State 2 ON 11 0 12 0 vdc Connect a DC voltmeter across RED and BLUE wires at connector PL13 then repeat COM 32 PONENT TEST by turning setup switch SW 6 OFF and then back ON Do you see approximately 34 33 the same DC voltages across RED and BLUE wires that you saw in Step 30 33 You have an open wire or bad terminal on either the RED or BLUE wire between connectors PL13 a _ 5 PL3 R
77. lculated RPM If this fault occurs in conjunction with fault 44 check wiring to motor otherwise refer to the trouble shooting guide 42 INDUCER OUTSIDE VALID SPEED RANGE Indicates the inducer is not operating at the calculated RPM or has not started within 10 seconds after a call for heat Check wiring to motor otherwise refer to the trouble shooting guide 43 PRESSURE SWITCH CALIBRATION FAULT Indicates the low and high pressure switch make points during high heat purge are not within the calibration range Check for Plugged condensate drain Water in vent piping possibly sagging pipe Improper pressure switch wiring or pressure switch tubing connections Failed or Out of Calibration pressure switches 44 BLOWER CALIBRATION FAULT Indicates the calculated blower speed is below 250 or above 1300 RPM Unit will default to low or high heat mode if possible If this fault occurs in conjunction with fault 41 check wiring to motor otherwise refer to the trouble shooting guide If this fault occurs by itself check for undersized ductwork or excessive static caused by a dirty filter or closed registers STATUS CODE EXAMPLE RED LED1 RED LED2 EMER HEAT MICROPROCESSOR MALFUNCTION DK UD UO DU W W1Y Y2 R 24 V 8 LMS MS 135 COUNT THE NO COUNT THE NO YELLOW LED3 OF FLASHES HIGH HEAT OF FLASHES 42 FAULT GREEN LED4 4 2 INDUCER
78. mostat lead then wait until blower motor stops 22 22 Are any LEDs flashing 24 23 zx 23 Are any LEDs on solid Solid means ON continuously 4 25 24 Is RED LED2 flashing 6 7 25 Put setup switch SW 1 in ON position 26 Record fault codes listed in fault history 26 NOTE Read fault codes until they repeat The last fault code that occurred will flash first fol 27 lowed by the lowest number fault code EXAMPLE 13 13 44 27 Are LEDs 3 and 4 flashing a Fault Code 11 29 30 28 Go to page number indicated in Index for subsection covering NO OPERATION WITH NO FLASH INDEX ING FAULT CODE 29 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 30 Go to page number indicated in Index for subsection covering first fault code flashed INDEX 31 Disconnect the R thermostat lead then wait until blower motor stops 32 32 Put setup switch SW 1 in ON position 33 Record fault codes listed in fault history 33 NOTE Read fault codes until they repeat The last fault code that occurred will flash first fol 34 lowed by the lowest number fault code EXAMPLE 13 13 44 34 Are LEDs 3 and 4 flashing a Fault Code 11 35 30 Go to page number indicated in Index for the CLEANUP AND START UP INSTRUCTIONS If this 35 problem persists on an intermittent basis replace furnace control board If problem still persists on INDEX
79. n a zone system make sure setup switch SW 5 is in ON position Check low fire rate Clock input rate DO NOT use manifold pressure method unless using propane Verify the following before going to Step 10 42 If unit is installed in a zone system make sure setup switch SW 5 is in ON position 10 Check high fire rate Clock input rate DO NOT use manifold pressure method unless using propane 25 Fault Code 34 IGNITION PROVING FAULT This fault can indicate 1 of the following Flame was not sensed during trial for ignition period The control will repeat ignition sequence 3 more times before going into Fault 14 IGNITION LOCKOUT The flame signal was lost after trial for ignition period The flame signal was sensed while gas valve was de energized The inducer will run at full speed until fault is cleared STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and disconnect R thermostat lead from furnace 2 trol board 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 Make sure thermostat is NOT calling for heat and reconnect R thermostat lead to furnace control 3 board Observe unit for 15 minutes Does inducer motor ever turn on at full speed while furnace 4 5 control board flashes Fault Code 34 4 Replace furnace cont
80. n main fuse box and furnace complies with wire size specification 6 in Installation Start Up and Operating Instructions 20 Disconnect the R thermostat lead 21 21 Do you have less than 17 vac between R and Com on furnace control board 22 23 22 Replace transformer x 7 Check the thermostat wire gage between furnace and thermostat and furnace and outdoor unit It is 23 recommended that AWG No 18 color coded copper thermostat wire be used for lengths up to 100 6 ft For wire lengths over 100 ft use AWG No 16 wire 24 Press down on microprocessor chip and make sure it is properly seated to furnace control board If e E 6 it is replace furnace control board Table 1 Air Conditioning A C Airflow Setup Switch Position AIR CONDITIONER AIRFLOW A C SWITCH POSITION ALLOWABLE FURNACE MODEL SETUP TONS CFM 040 060 080 080 100 120 1200 or 3 Tons 3 Tons 3 Tons 5 Tons 5 Tons 5 Tons 2000 1200 CFM 1200 CFM 1200 CFM 2000 CFM 2000 CFM 2000 CFM 1 1 2 600 mx 2 800 2 1 2 1000 1200 3 1 2 1400 4 1600 5 2000 X Indicates allowable selection Default 10 HIGH FIRE TEMPERATURE TOO LOW Generally this indicates the HIGH LOW solenoid in gas valve GV has failed or furnace is extremely underfired STEP ACTIO
81. nd electronics can be overstressed and may reduce the life of the components if operated for an extended period NOTE No safeties are bypassed when using emergency heat mode Emergency heat mode can be selected using setup switch SW 4 SW 4 should be used when a fault condition exists or difficult to resolve problems occur This allows heating until the fault can be corrected In emergency heat mode the normal heat mode outlined in Heating Mode section is not followed The following sequence will occur When thermostat calls for heat the R W W 1 circuits close 1 Prepurge period The inducer motor is turned on IMMEDI ATELY operating at maximum speed closing low and high pressure switches Prepurge begins 25 sec after high pressure switch closes 2 Blower on The blower motor is turned on IMMEDIATELY and slowly increases to maximum speed as soon as a call for heat is received No blower calibration occurs 3 Electronic Air Cleaner The EAC 1 terminal does not operate in emergency heat mode 4 Humidifier The HUM terminal is energized IMMEDI ATELY 5 Ignitor warm HSI is energized for a 17 sec warm up period after prepurge period is completed 6 Ignition sequence After HSI warm up period has com pleted the gas valve is energized permitting gas flow to burners where it is ignited After 5 sec the HSI is de energized and a 2 sec flame sensing period begins NOTE Emergency heat mode only oper
82. nd or humidifier 562 Replace entire blower motor including blower control module Inspect blower control module for wa _ _ 17 Appendix E Variable Speed Condensing Furnace Duct Static and Blower Operation This variable speed furnace has an Integrated Control and Motor called an ICM This ICM is controlled as stated in Sequence of Operation section This furnace does a good job compensating for an improperly sized duct system but this ICM is not a fix for all bad ductwork This troubleshooting guide has shown that the blower does a calibration 20 sec at start of any operation of ICM Note that blower calibration sequence is different when setup switch SW 5 is turned ON for multi zone operation See Sequence of Operation section These blower calibrations help to ensure proper airflow in heating and cooling In heating mode this calibration helps ensure proper temperature rise which prolongs life of heat exchanger In cooling mode this calibration helps ensure proper CFM per ton of cooling If furnace is on a call for heat or cooling and duct static is too high ICM tries to overcome external static pressure If duct static is excessive ICM RPM will be out of range and a Fault Code 44 will flash on circuit board The ICM RPM range is 250 to 1300 RPM as stated in Fault Code 44 troubleshooting section To check for excessive static pressure use the following Air Delivery Curves and Duct Static Check Sheet later in this Appendix EXAMPLE Furnac
83. nd restarts heating cycle If this happens on 2 consecutive cycles furnace control board locks out on Fault Code 12 During this sequence it is possible for furnace control board to start flashing Fault Code 41 instead of Fault Code 44 This indicates that blower calibration failed and blower speed during off delay is out of range When unit is operating in low heat and furnace control board date code 9505 or earlier is flashing Fault Code 44 it indicates that desired high heat blower RPM is greater than 1300 RPM and unit remains running in low fire mode for rest of heating cycle When unit is operating in high heat and furnace control board date code 9506 or later is flashing Fault Code 44 it indicates that desired high heat blower RPM is greater than 1300 RPM but furnace control board is running blower at default speed of 1200 RPM Under this condition the high fire temperature rise could be outside rise range and can cause limit cycling to occur COOLING TIf desired cooling blower RPM is less than 250 or greater than 1300 RPM furnace control board starts flashing Fault Code 44 and runs at default or previous cooling speed control signal for rest of cooling cycle During this sequence it is possible for furnace control board to start flashing Fault Code 41 instead of Fault Code 44 This indicates that blower calibration failed and blower speed for cooling is also out of range CONTINUOUS FAN TIf desired continuous fan blower RPM is les
84. nnection This blower speed reduction compensates for high humidity conditions during cooling operation on all furnace model sizes Reference Thermidistat Control Installation Start up and Op erating Instructions for further details Step 11 Zone Mode When setup switch SW 5 MZ is in ON position blower motor control is the same as above except with the following exceptions 1 While blower is operating in either low heat or continuous fan the coast down calibration is performed once a minute to update blower RPM for zone damper position changes during a given cycle NOTE Boards with date codes of 9506 or later will not perform a coast down calibration if blower pulse width to blower motor is greater than 60 percent This prevents nuisance faults from occurring when a high continuous fan CFM has been selected 2 While blower is operating in either high heat or cooling blower pulse width to blower motor is frozen when blower RPM is within 10 percent of calculated blower RPM for 5 sec START a problem exists the service technician should always begin troubleshooting here STEP ACTION YES NO GO TO 1 furnace door first DO NOT REMOVE BLOWER ACCESS PANEL Record status of LED s gt 2 1 4 See Service Label Fault Code Instructions Fig 4 2 Are any LEDs flashing 5 3 3 Are any LEDs on solid Solid me
85. ntinuity across auxiliary limit switch ALS 14 29 29 Can auxiliary limit switch ALS be reset 31 30 30 Replace auxiliary limit switch 9 31 Reset auxiliary limit switch ALS replace blower access panel turn power on set thermostat to call 3 32 for heat or jumper R and W W1 thermostat terminals and observe furnace operation for 15 minutes 32 Does fault occur again 38 33 33 Does a different fault occur 8 34 34 Is this unit in downflow or horizontal position 35 9 35 Me R thermostat lead wait for blower to stop and continue to observe unit for 5 more min IN 36 36 Does fault occur after blower stops 37 9 37 Increase blower off delay time to 225 sec by putting both setup switches SW 7 and SW 8 in ON _ _ 27 position 38 Does furnace have proper limit switch limit shield blower baffle if used rear air baffle if used 39 27 m and auxiliary limit switch If so are limit switch limit shield and heat exchangers properly aligned 39 Change limit switch first If problem still exists replace auxiliary limit switch One of these switches _ _ 9 is out of calibration 40 Does fault occur during low fire 41 42 On the third burner cycle unit will run in high fire mode and flash fault code continuously The unit is locked into high fire only mode Verify the following before going to Step 10 41 e unit has a bypass humidifier make sure setup switch Sw 3 is in ON position 10 If unit is installed i
86. ntrol box assembly from blower shelf and position out of the way 54 Removi ca ower from furnace m E 55 Disconnect both multi pin connectors from blower control module attached to the blower motor Be 55 56 sure to depress release latches on connectors or they may get damaged 56 Remove two 1 4 hex head bolts from blower control module attached to blower motor DO NOT 57 REMOVE TORX HEAD SCREWS located next to 1 4 hex head bolts Carefully lift blower control module off blower motor Depress latch on internal connector to discon 57 nect blower control module from motor portion of blower motor DO NOT PULL WIRES GRIP 58 PLUG ONLY When blower control module is completely detached from blower motor verify with standard ohm meter that the resistance from each motor lead in motor plug to unpainted motor end plate is 58 greater than 100k ohms Then verify motor windings are not shorted or open by measuring resis _ 2 59 tance between each combination of pins in motor plug there three different combinations pin 1 2 pin 2 3 and pin 1 3 Resistance should be approximately equal across each combination of pins 859 Did the motor pass the resistance check 60 62 60 Does blower wheel turn freely with blower control module removed 61 62 561 Replace blower control module Inspect failed blower control module for water damage If present 17 find source of water and fix Check A coil a
87. ol module attached to blower motor DO NOT E 50 REMOVE TORX HEAD SCREWS located next to 1 4 in hex head bolts Carefully lift blower control module off blower motor Depress latch on internal connector to discon 850 nect blower control module from motor portion of blower motor DO NOT PULL ON WIRES GRIP 51 PLUG ONLY When blower control module is completely detached from blower motor verify with standard ohm meter that the resistance from each motor lead in motor plug to unpainted motor end plate is 351 greater than 100k ohms Then verify motor windings are not shorted or open by measuring resis _ 52 tance between each combination of pins in motor plug there three different combinations 1 2 pin 2 3 and pin 1 3 Resistance should be approximately equal across each combination of pins 52 Did the motor pass the resistance check 53 55 853 Does blower wheel turn freely with blower control module removed 54 55 354 Replace blower control module Inspect failed blower control module for water damage If present m I 5 find source of water and fix Check A coil and or humidifier 555 Replace entire blower motor including blower control module Inspect blower control module for wa M 5 ter damage If present find source of water and fix Check A coil and or humidifier Fault Code 13 LIMIT SWITCH LOCKOUT This fault indicates the limit switch has tripped 10 times in a row in high fire or 3 times in a row
88. om on furnace control board to know when high pressure switch HPS makes 67 Does fault occur a few sec after main burners ignite 63 68 68 Observe operation of furnace in high heat for next 8 minutes or until fault occurs 69 69 Does the fault occur 22 59 70 If problem still persists check for internal restriction in coupling box or secondary heat exchangers 14 Fault Code 43 PRESSURE SWITCH CALIBRATION FAULT Indicates low pressure switch LPS and high pressure switch HPS make points during high heat purge are not within calibration range This is determined by reading inducer motor RPM when low pressure switch LPS and high pressure switch HPS make Then the following comparison is made RPM low If this relationship is not within range specified furnace control board starts flashing fault colde 43 shuts unit down inducer runs for 15 sec waits 2 minutes stops flashing fault code and restarts heating cycle It can also indicate that the high pressure switch HPS made before the low pressure switch LPS during either low heat or high heat purge STEP ACTION GO TO 1 Turn power off remove blower access panel and disconnect all thermostat leads from furnace con 2 E trol board 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Jumper R W W1 and W2 thermostat terminals on furnace control board 4 30
89. on furnace control board 13 15 Make sure wire gage between main fuse box and furnace complies with wire size specification in 13 Installation Start Up and Operating Instructions m 14 Fix problem E ES 8 15 Disconnect R thermostat lead 16 16 Is RED LED2 ON 17 18 17 Replace transformer pens 8 Check thermostat wire gage between furnace and thermostat and furnace and outdoor unit It is 18 recommended that AWG No 18 color coded copper thermostat wire be used for lengths up to 100 14 ft For wire lengths over 100 ft use AWG 16 wire 19 Disconnect all thermostat leads from furnace control board 20 20 Put setup switch SW 1 ON position and jumper W W1 and Y Y2 thermostat terminals 21 21 Does RED LED2 turn OFF 22 7 22 Put setup switch SW 1 back in OFF position 23 23 Turn power off and reconnect thermostat leads to furnace control board 24 24 Turn power on 25 25 Does RED LED2 turn back ON 26 36 26 Disconnect all thermostat leads from thermostat control board 27 27 Put setup switch SW 1 in ON position and jumper R W W1 and Y Y2 thermostat terminals simulta 28 neously until RED LED2 turns OFF 11 28 Put setup switch SW 1 back in OFF position 29 29 Jumper and W W1 thermostat terminals 30 30 Does R
90. on of furnace for next 8 minutes or until fault occurs 5 5 Does Fault Code 44 flash twice followed by Fault Code 41 7 6 After about 10 minutes of operation furnace will lock out and flash Fault Code 12 Go to page num INDEX ber indicated in Index for Fault Code 12 7 Does only Fault Code 41 flash 8 8 Does a different fault occur 25 9 Go to page number indicated in Index for fault code flashed INDEX 10 Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS INDEX 11 Does blower motor suddenly stop 10 sec before fault is signaled 21 12 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 13 13 Put setup switch SW 4 labeled EMER HEAT in ON position 14 14 Turn power on and wait several sec then jumper R and W W1 thermostat terminals on furnace 15 trol board 15 Check connectors PL3 PL10 PL11 PL12 PL13 B1 and B2 16 16 Does motor operate intermittently in response to connectors and wires being moved 18 17 Fix problem 10 18 Does blower motor suddenly stop 20 Replace entire blower motor or blower control module attached to the blower motor If you replace 19 the blower control module go to step 26 If problem still persists an intermittent basis after re INDEX placing blower motor or blower control module contact your distributor 20 Replace furnace control board 10 21 Turn power off and disconnect jumper
91. ontrol board starts flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle If low pressure switch LPS opens before ignition furnace control board starts flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle 2 STEADY STATE If low pressure switch LPS opens during high heat furnace control board starts flashing Fault Code 32 shuts unit down waits 2 minutes stops flashing Fault Code 32 and restarts heating cycle STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and disconnect R thermostat lead 2 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Is inducer motor MTR1 running 4 5 4 Are inducer motor MTR1 and blower motor MTR2 running 13 49 5 Jumper R and W W1 thermostat terminals on furnace control board 6 6 Observe operation of furnace through 1 heating cycle 7 7 Does fault occur again 11 8 8 Does a different fault occur 9 10 9 Go to page number indicated in Index for fault code flashed INDEX 10 Go to page number indicated in Index for CLEANUP AND STARTUP INSTRUCTIONS INDEX 11 Does fault occur within 5 sec after a call for heat 12 17 12 Do you have 24v between N O Normally Open contact on low pressu
92. or switch Use a piece of tape to hold switch closed Wait a few sec 36 for self test before proceeding to next step 36 Do you have 120v between B1 and B2 on furnace control board 37 16 37 Do you have 120v between BLACK and WHITE power leads at blower motor MTR2 39 38 38 You have an open wire or bad terminal on either the BLACK or WHITE wire between furnace con _ _ 17 trol board and blower motor MTR2 Repair it or replace blower harness es Check Blower ON OFF line To do this connect a DC voltmeter across terminals PL3 1 RED and PL3 5 BLUE then put setup switch SW 6 for COMPONENT TEST in ON position Does 39 voltage across RED and BLUE wires change between states as shown below 42 40 State 1 0 1 0 1 vdc State 2 ON 9 0 10 0 vdc Disconnect PL3 from furnace control board and connect a DC voltmeter across terminals PL3 1 and PL3 5 on furnace control board Repeat COMPONENT TEST by turning setup switch SW 6 40 OFF and then back ON Does voltage across PL3 1 and PL3 5 change between states as shown 33 22 below State 1 0 1 0 1 vdc State 2 ON 11 0 12 0 vdc You have an open wire or bad terminal on either the RED or BLUE wire between connectors PL13 41 A 17 and PL3 Repair it or replace blower harness es Connect a DC voltmeter across RED and BLUE wires at connector PL13 Repeat COMPO NENT TEST by turning setup switch SW 6 OFF and then back ON
93. otherwise repair wire or replace harness Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals Discon 21 nect BROWN wire from N O Normally Open contact on high pressure switch HPS Turn power on 22 and wait a few sec for self test then reconnect jumper across R and W W1 thermostat terminals 22 Does a Fault Code 32 occur 23 23 Reconnect BROWN wire to Normally Open contact on high pressure switch HPS 24 24 The problem may be caused by a sag in vent pipe If this is not the problem and fault still occurs E 8 replace pressure switch assembly 25 The vent tube to drain trap drain trap or drain line is clogged 10 31 Fault Code 44 BLOWER CALIBRATION FAULT This fault indicates that calculated blower motor speed is below 250 or above 1300 RPM When Fault Code 44 occurs in HEATING COOLING or CONTINUOUS FAN mode unit operates as shown below Keep in mind that whenever furnace control board shuts unit down in heating mode gas shuts off immediately inducer continues running for 15 sec and blower runs at default or previous speed control signal for selected off delay HEATING During a call for heat the desired low heat and high heat blower RPMs are calculated at the same time If desired low heat blower RPM is less than 250 or greater than 1300 RPM furnace control board starts flashing Fault Code 44 shuts unit down waits 2 minutes stops flashing Fault Code 44 a
94. ower off and disconnect jumper wire across R and W W1 thermostat terminals 20 20 Turn power on and wait several sec then jumper R W W1 and W2 thermostat terminals on fur n u 21 nace control board 21 Does Fault Code 14 start flashing when high pressure switch HPS makes 22 14 22 The BLUE and GREEN wires to gas valve GV are reversed 17 23 Does fault occur during low fire after blower turns on 24 29 24 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 25 21 Connect 1 side of a slope manometer with a tee to collector box pressure tap Connect other side 25 with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix m 28 26 power on and wait several sec then jumper W W1 thermostat terminals furnace con DE 27 trol board 27 Monitor slope manometer Does pressure reading appear to be stable when fault occurs 14 28 28 Check for a sag in vent pipe If problem persists replace inducer motor 8 29 Disconnect jumper wire across R and W W1 thermostat terminals and wait until blower stops 30 30 Jumper R W W1 and W2 thermostat terminals on furnace control board 31 31 Does high pressure switch HPS make then break several times at start of cycle before faulting out 32 33 32 The problem is either
95. pass Damper being used What type of Bypass Humidifier is being used Is Bypass Humidifier setup switch on or off and is it operating opening If you have a Fault Code 41 and or 44 do the following 1 Turn power off to furnace and outdoor unit Set A C setup switch for 2 tons 800 CFM Turn only power to furnace back on 2 3 4 Set thermostat for a call for cooling 5 Check supply and return ESP as in Appendix E Add these 2 ESP readings together for Total ESP Repeat these steps until a fault code flashes on the microprocessor Log your information on this sheet At Low Heat Supply ESP Return ESP Any Fault Code Flashing At High Heat Supply ESP Return ESP Any Fault Code Flashing At 2 Ton Setting Supply ESP Return ESP Any Fault Code Flashing At 2 5 Ton Setting Supply ESP Return ESP Any Fault Code Flashing At 3 Ton Setting Supply ESP Return ESP Any Fault Code Flashing At 3 5 Ton Setting Supply ESP Return ESP Any Fault Code Flashing At 4 Ton Setting Supply ESP Return ESP Any Fault Code Flashing At 5 Ton Setting Supply ESP Return ESP Any Fault Code Flashing Before or After Evaporator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number Before or After Eva
96. perature rise in Step 22 more than 10 F higher than the temperature rise in Step 19 24 8 24 Disconnect jumper wire across R and W W1 thermostat terminals and wait until blower stops m 25 25 Remove blower access panel and put setup switch SW 3 in ON position 26 Cycle furnace with blower access panel in place and record the temperature rise across return air 26 duct before and after the bypass gt 27 Is temperature rise from bypass greater than 15 28 29 28 The bypass is oversized Adjust damper or replace with properly sized bypass 9 29 Disconnect jumper wire across R and W W1 thermostat terminals and wait until blower stops 30 30 Does the installation have modulating zone dampers 31 51 31 Is setup switch SW 5 in ON position 33 32 32 Put setup switch SW 5 in ON position 9 33 Jumper and W W1 thermostat terminals on furnace control board 34 Does blower recalibrate every minute Check by monitoring DC voltage across terminals PL3 1 34 RED and PL3 5 BLUE If DC voltage momentarily goes down to 0 vdc approximately every 35 8 60 sec after first blower calibration then blower is recalibating properly 35 Disable modulating zone damper System with all dampers in open position except bypass damper 36 If the installation is equipped with bypass damper it should be in the closed position Put setup switch SW 2 in OFF position Disconnect jump
97. porator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number Before or After Evaporator Coil Before or After Filter If so what number 44 Appendix Quick Reference Information PRESSURE SWITCH MAKE BREAK POINTS HIGH PRESSURE SWITCH LOW PRESSURE SWITCH Make Point Break Point Make Point Break Point 40 000 1 81 in wc max 1 63 in wc 0 05 0 75 in wc max 0 60 in wc 0 05 60 000 80 000 m 100 000 1 81 1 63 wc 0 05 0 95 in wc 0 80 in wc 0 05 120 000 UNIT SIZE BTUH FLAME SENSOR MICORAMPERAGE Microamp Range 0 5 to 6 0 microamps Typical Reading 4 to 6 microamps HOT SURFACE IGNITOR OHM READING Ohm reading of HSI unused 45 to 90 ohms resistance will go up over time GAS VALVE OHM READINGS M to C 98 ohms solenoid coil Hito C 1 5 ohm Bridge Rectifier Use diode test function setting on ohm meter POWER CHOKE When you put unit into component test function measure motor amp draw before power choke Then repeat component test but this time measure amp draw without power choke in line The amp draw should be higher without power choke Some ammeters will register a lower amp draw look for a
98. r airflow than setting STEP ACTION GO TO 1 Turn power off and remove blower access panel 2 2 Are air conditioning select switches A C set properly See Table 2 3 Set air conditioning select switches A C for proper tonnage as required by condensing unit 4 4 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 5 Are continuous fan select switches CF set properly See Table 3 Set continuous fan select switches CF for desired airflow This setting should normally be set to DE 6 FAULT position unless a 2 speed AC HP is part of system Use Table 4 for reference on 2 speed 4 AC HP airflow requirements 7 Are continuous fan select switches CF set to a higher airflow than air conditioning select switches _ See Tables 2 and 3 8 Is furnace a 100 size 9 The problem is in the A C or CF selection circuit The maximum cooling or continuous fan airflow for 10 this unit will be delivered 10 age A C and CF switches back and forth If fault code continues to flash replace furnace control 4 11 is in the A C or CF selection circuit The minimum cooling or continuous fan airflow for 12 this unit will be delivered 12 age A C and CF switches back and forth If fault code continues to flash replace furnace control 4 18 Table 2 Conditioning Airflow Setup Switch Position
99. re switch LPS and Com on 14 47 furnace control board 13 Replace furnace control board 10 14 Is low pressure switch LPS wired correctly 16 15 15 Rewire low pressure switch LPS per wiring diagram 10 16 Replace pressure switch assembly 10 17 At start of cycle as inducer is ramping up does low pressure switch LPS make then break 34 18 418 Does fault occur after ignition but before the blower comes on 55 54 19 Do you have 24v between C Common on low pressure switch LPS and Com on furnace control 24 20 board 20 Do you have 24v between connector terminal PL2 1 and Com on furnace control board 21 13 21 Turn power off zum E 22 22 check continuity between C Common on low pressure switch LPS and connector terminal 27 23 23 YELLOW wire to low pressure switch LPS is not making good connection Repair or replace it 10 Do you have at least 0 95 wc pressure drop 0 75 wc on trophy unit across heat exchangers 24 when fault occurs Determine this by connecting 1 side of a slope manometer with a tee to collector 35 25 E box pressure tap Connect other side with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix C 25 Is inducer motor MTR1 rotating in direction indicated on inducer housing 28 26 26 Replace inducer motor or inducer motor assembly 10 27 Fix problem 10 28
100. ressure switch wiring or pressure switch tubing connections Failed or Out of Calibration pressure switches 32 LOW PRESSURE SWITCH FAULT Indicates low pressure switch is closed at call or fails to close after call or opens during operation Check for Plugged condensate drain Water in vent piping possibly sagging pipe Improper pressure switch wiring or pressure switch tubing connections Failed or Out of Calibration pressure switches 33 LIMIT OR FLAME ROLL OUT SWITCH IS OPEN Indicates the limit rollout switch or auxiliary limit switch is open or the unit is operating in high heat only mode due to two successive low heat limit trips Check for Improper or misaligned limit and or limit shield Improper low heat gas input adjustment Stuck high heat solenoid in gas valve 9924 34 IGNITION PROVING FAULT Control will try three more times before a lockout 14 occurs Check for Gas valve defective or gas valve turned OFF Defective Hot Surface Ignitor Manual valve shut off Low inlet gas pressure Flame sensor must be ungrounded Green wire MUST be connected to furnace sheet metal Proper flame sense microamps 5 microamps D C minimum 4 0 6 0 nominal in HIGH HEAT Inadequate flame carryover or rough ignition Control ground continuity Oxide buildup on flame sensor clean with fine steel wool 41 BLOWER OUTSIDE VALID SPEED RANGE Indicates the blower is not operating at the ca
101. ressure tap Connect other side m 43 with a tee to gas valve air pressure fitting Refer to pressure check diagram in Appendix C Turn power and wait several sec then jumper R and W W1 thermostat terminals on furnace con trol board lt 5 m i 44 Monitor slope manometer Does pressure reading appear to be stable when fault occurs 45 46 45 Replace pressure switch assembly If problem persists check wiring for an intermittent connection m ax 10 in low pressure switch LPS circuit 46 Check for a sag in vent pipe If problem persists replace inducer motor 10 47 Do you have 24v between connector terminal PL2 2 and Com on furnace control board 48 13 48 The main harness is miswired 27 Check Inducer PW line To do this disconnect PL7 from inducer motor and connect DC voltmeter across terminals PL7 2 BROWN and PL7 10 YELLOW then run COMPONENT TEST by turning setup switch SW 6 ON Does voltage across PL7 2 and PL7 10 change between states as 49 shown below 26 13 State 1 OFF 0 1 0 1 State 2 LOW 6 0 7 0 vdc State 3 HIGH 10 5 11 5 vdc 50 Does inducer motor MTR1 turn on 19 51 51 Do you have less than 90 vac between I1 and I2 on furnace control board 53 52 Check Inducer PW line To do this disconnect PL7 from inducer motor and connect a DC voltmeter across terminals PL7 2 BROWN and PL7 10 YELLOW then run COMPONENT TE
102. rminals Turn power 16 on and wait a few sec for self test before proceeding to next step 16 Put setup switch SW 4 for EMER HEAT in ON position 17 17 Jumper and W W1 thermostat terminals on furnace control board 18 18 Does inducer motor turn on 30 19 19 Does inducer wheel rub against inducer housing 14 20 20 Turn power off 21 21 Does inducer wheel turn freely 24 22 ma 22 Replace inducer motor or inducer motor assembly 8 23 Replace furnace control board 8 24 Disconnect jumper wire across R and W W1 thermostat terminals and put setup switch SW 4 for _ _ 25 HEAT in OFF position 25 Turn power on and wait a few sec for self test before proceeding to next step 26 26 Check 12 vdc line To do this connect a DC voltmeter across terminals PL1 6 BROWN and 27 23 a PL1 7 GREEN Is voltage across BROWN and GREEN wires 11 5 12 5 vdc 27 Turn power off m 28 28 Do you have continuity between PL7 2 and PL1 6 22 29 29 You have an open wire or bad terminal on BROWN wire between connectors PL7 and PL1 14 30 Disconnect jumper wire across R and W W1 thermostat terminals and put setup switch SW 4 for A _ 31 HEAT in OFF position Check RPM feedback line To do this connect a DC voltmeter across terminals PL1 6 BROWN and PL1 5 ORANGE then put setup switch SW 6 for COMPONENT TEST in ON position Does 31 voltage across BROWN and OR
103. rol board Make sure it has a date code 9405 or later 12 5 Disconnect R thermostat lead from furnace control board and jumper and W W1 thermostat termi M m 6 nals on furnace control board 6 Observe operation of furnace through 1 heating cycle 7 7 Does fault occur again 13 8 8 Does a different fault occur 9 10 9 Go to page number indicated in Index for fault code flashed INDEX 10 Disconnect jumper wire across R and W W1 thermostat terminals Does fault occur now 11 12 11 Replace gas valve m 12 12 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 13 Turn power off and disconnect jumper wire across R and W W1 thermostat terminals 14 14 Turn power on and wait several sec before proceeding to next step 15 15 Check hot surface ignitor To do this put setup switch SW 6 for COMPONENT TEST in ON posi 20 16 tion Does ignitor glow orange white hot by end of 15 sec warm up period Disconnect PL4 from furnace control board Connect an AC voltmeter across PL4 1 and PL4 2 on 16 furnace control board Repeat COMPONENT TEST by turning setup switch SW 6 OFF and then 18 17 back ON Do you see 120 vac across PL4 1 and PL4 2 during 15 sec warm up period 17 Replace furnace control board 12 18 Check continuity in harness and ignitor Replace defective component 19 19 Fix problem 8 20 Put setup switch SW 6 for
104. s than 250 or greater than 1300 RPM furnace control board will start flashing Fault Code 44 and run at default or previous continuous fan speed control signal for the rest of continuous fan cycle During this sequence it is possible for furnace control board to start flashing Fault Code 41 instead of Fault Code 44 When this happens it indicates blower calibration failed and blower speed for continuous fan is also out of range STEP ACTION YES NO GO TO Turn power off wait 30 sec then restore power Reset thermostat Observe operation of furnace 1 through 1 heating cycle mE 2 NOTE Blower access panel must be in place 2 Does Fault Code 44 flash twice followed by Fault Code 41 3 4 3 Eventually furnace will lock out on Fault Code 12 given enough time Go to page number indicated a INDEX E in Index for Fault Code 12 4 Does only Fault Code 44 occur 8 5 5 Does a different fault occur 6 11 6 Go to page number indicated in Index for fault code flashed INDEX 7 Go to page number indicated Index for CLEANUP AND START UP INSTRUCTIONS INDEX 8 Does unit operate in low fire while flashing Fault Code 44 9 3 You have excessive restriction in air delivery system Check filter s and ductwork If problem still 9 persists replace furnace control board Make sure replacement board has a date code of 9506 or E 10 d later This new furnace control board w
105. sists on an intermittent INDEX basis after replacing blower motor contact your distributor 40 Turn power off and remove blower access panel Depress door switch Use a piece of tape to hold j 41 switch closed Wait few sec for self test before proceeding to next step 41 Disconnect all thermostat leads from furnace control board If blower motor is running wait until it I3 42 stops 42 Jumper R and G thermostat terminals Observe operation of furnace for next 30 sec 43 Approximately 20 sec after energizing G thermostat terminal does blower motor pause briefly less 43 than1 2 sec 3 18 2 Note You can verify this pause using a clamp on ammeter on BLACK power lead to blower motor MTR2 14 WARNING Wait at least 5 minutes after disconnecting line voltage from equipment before opening blower motor to prevent electric shock which can cause personal injury or death 44 Remove tape from door switch and turn power off at main disconnect 45 45 Disconnect PL10 from blower assembly TEN 46 46 Remove control box assembly from blower shelf and position out of the way 47 4T Remove blower assembly from furnace 48 Disconnect both multi pin connectors from blower control module attached to the blower motor Be 48 49 sure to depress release latches on connectors or they may get damaged 349 Remove two 1 4 in hex head bolts from blower contr
106. ted in NO column Let s try our guide out using the EXAMPLE section below and see how it works Suppose that the problem is a defective low pressure switch for example will not make This is an internal problem and cannot simply be seen We go to the START HERE section to Step 1 Additional Service Tools are available for current variable speed condensing furnaces The Advanced Product Monitor Kit KGAFPO0101APM includes a harness and diskette that allows communication with the control board through a personal com puter RS 485 adapter required The ICM Motor Simulator Kit KGASDO101FMS is a plug in device to help trooubleshoot ICM inducer and blower motors and control boards Reference price pages for current kit numbers SEQUENCE OF OPERATION CAUTION Furnace control must be grounded for proper operation or control will lock out Control is grounded through green wire routed to gas valve and burner box screw Using schematic diagram see Appendix A follow sequence of operation through different modes This furnace has a new control system Read and follow wiring diagram carefully NOTE If 115 v power supply to furnace or blower access panel switch is interrupted during a call for heat blower operates at low heat speed for 60 sec when power is restored before heating cycle is resumed Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring o
107. tem be designed for sum of the peaks plus 2596 oversize to allow furnace to operate within its design parameters Contact your distributor for further details 40 External Static Pressure in wc External Static Pressure in wc External Static Pressure in wc Air Delivery Curves Air Delivery Curve 040 14 Constant System Curves 215 Ton 900 1000 1100 1200 1300 1400 1500 CFM A93074 Air Delivery Curve 080 14 Constant System Curves External Static Pressure in wc 215 Ton 3 Ton 315 Ton 500 600 700 800 900 1000 1100 1200 1300 1400 1500 97320 Air Delivery Curve 100 20 HIGH 08 NBEAT Constant System Curves v 0 7 0 6 Ca a 0 5 T 2 LOW 4 HEAT 2 7 1 7 27 1 2 0 3 2 2 27 PT T Po ge 2 247 md en 02 gt i a See 4 0 2 215 3 31 Ton 4 5 700 900 1100 1300 1500 1700 1900 2100 97322 41 External Static Pressure in wc External Static Pressure in wc Air Delivery Curve 060 14 Constant System Curves 2 Ton 500 600 700 800 900 1000 1100 1200 1300 1400 1500 97319 Air Delivery Curve 080 20 Constant System Curves
108. trol center holds gas valve open and begins blower on delay period NOTE Ignition sequence repeats 3 additional times before a lockout occurs Lockout automatically resets after 3 hr or can be manually reset by turning 115 v or 24 v power off not at thermostat for 3 sec minimum then turning on again 6 Inducer speed reduction If cycle starts in low heat inducer speed reduces slightly after the flame sense If cycle starts in high heat inducer speed increases 15 sec after flame sense The reduction in speed in low heat is to optimize combustion for maximum efficiency Step 7 tells us to go to low pressure switch fault subsection 7 Blower on delay tThe blower starts 60 sec after flame sense if cycle started in low heat or 35 sec after flame sense if cycle started in high heat NOTE The blower starts at approximately 400 500 RPM After 20 sec the motor is turned off for 1 10 of a sec where a coast down calibration is done to evaluate resistance of the conditioned air duct system The microprocessor then determines blower RPM required to provide proper airflow for heating mode 8 Electronic Air Cleaner The EAC 1 terminal is energized whenever the blower operates 9 Blower off delay When thermostat is satisfied the R W W1 signal is terminated de energizing gas valve stopping gas flow to burners and HUM terminal is de energized The blower reduces its speed to low heat RPM The blower and EAC remain op
109. uld be mid range or slightly 14 higher than midpoint of range stated on furnace rating plate If return temperature is below 60 F 15 condensation may form on heat exchangers If left uncorrected failure will result 15 Check return air ducts in unheated spaces for leaks 9 LEDs 1 2 3 or 4 ON SOLID SOLID means on continuously RED LEDI ON SOLID indicates furnace is operating in emergency heat RED LED2 ON SOLID indicates microprocessor has malfunctioned or secondary voltage to furnace control board is low YELLOW LED3 ON SOLID indicates furnace is operating in high fire GREEN LED4 ON SOLID indicates furnace is operating in low fire STEP ACTION YES NO GO TO 1 Turn power off and remove blower access panel 2 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Jumper R W W1 thermostat terminals on furnace control board 4 4 Is RED LED1 ON 5 9 5 Is setup switch SW 4 labeled EMER HEAT in ON position 6 7 6 Put setup switch SW 4 labeled HEAT in OFF position 8 7 Replace furnace control board 8 8 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 9 Disconnect jumper wire across R and W W1 thermostat terminals 10 10 Is RED LED2 ON 11 32 11 Do you have less than 17 vac between R and Com on furnace control board 12 19 12 Do you have less than 90 vac between P1 and P2
110. ult Code 14 flash 3 6 m 3 There is a miswire or short to gas valve wiring 4 4 Fix problem 5 5 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 6 Does a different fault occur 7 8 7 Go to page number indicated in Index for the fault code flashed INDEX 8 Remove blower access panel and depress door switch Use a piece of tape to hold switch closed 9 9 Jumper and W W1 thermostat terminals 10 10 Does Fault Code 14 start flashing when low pressure switch LPS makes 11 12 11 Replace furnace control board mE 5 12 Does a different fault occur 7 13 13 Disconnect jumper wire across and W W1 2 thermostat terminals and wait until blower stops 14 14 Jumper W W1 and W2 thermostat terminals on furnace control board 15 15 Does Fault Code 14 start flashing when high pressure switch HPS makes 16 17 16 The BLUE and GREEN wires to gas valve GV are reversed 4 17 Disconnect jumper wire across R W W1 and W2 thermostat terminals and wait until inducer stops 18 18 Put setup switch SW 1 in ON position 19 Is a Fault Code 34 present in fault history 19 NOTE Read fault codes until they repeat The last fault code that occurred will flash first fol 20 22 lowed by the lowest number fault code EXAMPLE 14 14 34 20 Cycle furnace several times to check for intermittent operation
111. urrent near typical value 39 38 38 Replace electrode 12 39 Will main burners ignite and stay on 12 17 40 Do you have combustion pulsations 41 47 26 41 sure perforated disks are in combustion air vent inlet 42 42 Check pressure tubing going to gas valve air pressure fitting for kinks 43 43 Remove gas valve air pressure fitting and check gas valve for blockage 44 44 Ensure vent and combustion air pipes are not reversed 45 45 Check burner orifice size and alignment 46 46 Add restriction to combustion air pipe or lengthen it a few feet if possible 12 4T Jumper R and W2 thermostat terminals on furnace control board 48 48 Do you have combustion oscillations in high fire 41 12 BLOWER OUTSIDE VALID SPEED RANGE This fault indicates 1 of the following Blower motor speed cannot be maintained within 1096 of calculated speed over a 30 sec period Blower motor speed is less than 250 RPM or greater than 1300 RPM for more than 10 sec STEP ACTION NO GO TO 1 Turn power off remove blower access panel and disconnect thermostat lead from furnace con m 2 trol board 2 Turn power on and depress door switch Use a piece of tape to hold switch closed 3 3 Jumper R and W W1 thermostat terminals on furnace control board 4 4 Observe operati
112. witch closes inducer motor RPM is noted by microprocessor and a 25 sec prepurge period begins The RPM is used to evaluate vent system resistance This evaluation is then used to determine required RPM necessary to operate inducer in low heat mode NOTE The heat cycle can start in either high or low heat If a high heat cycle is initiated inducer continues increasing its speed after low pressure switch closes When high pressure switch closes inducer motor RPM is noted by microprocessor before the 25 sec prepurge period begins The RPM is used to evaluate vent system resistance This evaluation is used to determine required RPM necessary to operate inducer in high heat mode 2 Humidifier The HUM terminal is energized whenever in ducer prepurge period is completed 3 Ignitor warm up After prepurge period HSI is energized for 17 sec 4 Ignition sequence After HSI warm up period is completed the gas valve is energized permitting gas flow to the burners where it is ignited After 5 sec the HSI is de energized and a 2 sec flame sensing period begins 5 Flame sensing When burner flame is sensed control center holds gas valve open If burner flame is not sensed control center de energizes gas valve and ignition sequence is repeated Blower off period Ten sec after gas valve is energized the blower stops for 25 sec to allow heat exchangers to warm up 7 Blower on delay After blower off period blower starts
113. with no fault code no inducer post purge no blower off de 35 38 lay and then restart heating cycle 35 Disconnect BROWN wire to gas valve GV 36 36 Does furnace still abruptly shut down with no fault code no inducer post purge no blower off delay 39 37 n and then restart heating cycle 37 Replace gas valve 8 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS If problem 38 persists on an intermittent basis replace furnace control board If problem still persists after replac INDEX ing furnace control board contact your distributor 39 Disconnect humidifier lead from HUM terminal on furnace control board 40 40 Does furnace still abruptly shut down with no fault code no inducer post purge no blower off delay 33 32 and then restart heating cycle NOT ENOUGH COOLING AIRFLOW Generally this indicates the Y Y2 thermostat lead is not properly connected STEP ACTION YES NO GO TO 1 Remove blower access panel and depress door Switch Use a piece of tape to hold switch closed Y 2 li Wait a few sec for self test before proceeding to next step 2 Make sure thermostat is calling for cooling If thermostat lead G is not connected jumper across _ 3 thermostat terminals R and G 3 Make sure thermostat fan control is in AUTO position if equipped 4 4 Do you have 24v across Y Y2 and Com on furnace control board 8 5 5 You have a

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