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31-5000736   Rev. 0   11-22   GEA

NF80DS

80% Downflow Single Stage 

Constant Torque Gas Furnace

Service 

Manual

READ  CAREFULLY.   

KEEP THESE INSTRUCTIONS

.

Summary of Contents for GE APPLIANCES NF80D045S3A

Page 1: ...31 5000736 Rev 0 11 22 GEA NF80DS 80 Downflow Single Stage Constant Torque Gas Furnace Service Manual READ CAREFULLY KEEP THESE INSTRUCTIONS ...

Page 2: ... you see this symbol on labels or in manuals be alert to the potential for personal injury or death Electric shock hazard Can cause injury or death Before attempting to perform any service or maintenance turn the electrical power to unit OFF at disconnect switch es Unit may have multiple power supplies WARNING As with any mechanical equipment contact with sharp sheet metal edges can result in pers...

Page 3: ... 1 15 6 8 40 119 NF80D070S3B 66 000 54 000 80 00 2 3 1 2 120 60 1 15 6 8 40 128 NF80D090S4B 88 000 72 000 80 00 3 4 1 2 120 60 1 15 8 4 40 140 NF80D110S5C 110 000 90 000 80 00 4 5 1 2 120 60 1 15 10 9 40 160 Note For vent sizing and clearances to combustibles please reference installation instructions MAJOR MINOR REVISION CABINET WIDTH A 14 5 B 17 5 C 21 NOMINAL CFM 3 1200 CFM 4 1600 CFM 5 2000 CF...

Page 4: ...ow 1090 1055 1025 990 955 915 890 Low 920 900 845 820 770 730 675 NF80D070S3B 1 2 10 x 10 30 60 High 1400 1360 1310 1280 1250 1220 1165 Med High 1230 1205 1155 1110 1060 1000 935 Med 1125 1085 1050 985 935 865 795 Med Low 1110 1055 1000 950 865 815 750 Low 900 845 790 705 645 590 480 NF80D090S4B 3 4 10 x 10 30 60 High 1695 1660 1615 1570 1545 N A N A Med High 1470 1425 1395 1360 1295 1265 1215 Med...

Page 5: ... Kit 11K50 Single Stage 11K45 High Altitude Downflow Combustible Flooring Base 11M59 14 5 A Width 11M60 17 5 B Width 11M61 21 0 C Width Twinning Kit 16W72 Constant Torque Gas Furnace Twinning Kit Note For vent length and clearances to combustibles please reference installation instructions ...

Page 6: ...air inducer Control Box includes integrated control interlock switch and transformer Gas Valve Burner Box includes sensor ignitor and rollout switches Combustion Air Inducer Blower Access Panel Heating Compartment Access Panel Heat Exchanger Flue Chase Blower Assembly Secondary Limit ...

Page 7: ...es overcurrent protection to the transformer T1 The breaker is rated at 3A at 32V If the current exceeds this limit the breaker will trip and all unit operation will shutdown The breaker can be manually reset by pressing the button on the face Integrated Ignition Control Shock hazard Disconnect power before servicing Control is not field repairable If control is inoperable simply replace entire co...

Page 8: ...4 Low Flame Signal check flame sensor 5 Soft lockout burner failed to light exceeded maximum number of retries or recycles 6 Not Used 7 Primary or Secondary Limit Open or Soft Lockout Mode Limit Switch Open longer than 3 minutes 8 Rollout Switch Open 9 Pressure Switch failed to close or opened during heat demand 10 Soft lockout Pressure Switch opened 5 times during one heat demand 11 Pressure Swit...

Page 9: ...p time between trials of 35 seconds After a total of five trials for ignition including the initial trial the integrated control goes into Soft Lockout Flame Failure mode After a 60 minute reset period the integrated control will begin the ignition sequence again Fan Time Control Heating Fan On Time The fan on time of 30 seconds is not adjustable Heating Fan Off Time Fan off time time that the blo...

Page 10: ...is a high temperature limit Each furnace is equipped with two identical switches The limit is a N C SPST manual reset limit connected in series with the integrated control A92 When S47 senses rollout the integrated control immediately stops ignition and closes the gas valve If unit is running and flame rollout is detected the gas valve will close and integrated control will be disabled Rollout can...

Page 11: ...Valve Figure 6 The NF80DS uses an internally redundant valve to assure safety shut off If the gas valve must be replaced the same type valve must be used 24VAC terminals and valve switch are located on the valve All terminals on the gas valve are connected to wires from the integrated control 24V applied to the terminals energizes the valve Inlet and outlet pressure taps are located on the valve A...

Page 12: ...rol Remove Sensor Wire from Integrated Control and Connect Alligator Clip to Flame Sensor Lead Flame Sensor Terminal Remove Sensor Wire from Integrated Control and Connect Alligator Clip to Terminal on Control DIGITAL METER To Control Sensor Terminal To flame sensor Set dial to measure dc microamps Red Collar Indicates Positive Lead ...

Page 13: ...esistance of ignitor at the plug Reading should be between 39 and 70 ohms If the reading is correct then the problem is with the wiring between the jack plug and the control If reading is not correct the issue is the ignitor Test 3 Check ignitor for correct voltage Insert meter probes into terminals 2 and 4 use small diameter probes in order not to damage plug Check voltage during 20 second ignito...

Page 14: ...The switch is a single pole single throw proving switch electrically connected to the furnace control The purpose of the switch is to prevent burner operation if the combustion air inducer is not operating or if the flue becomes obstructed On start up the switch senses that the combustion air inducer is operating It closes a circuit to the integrated control when pressure inside the combustion air...

Page 15: ...ests 1 and 2 and motor is not operating properly replace motor The motor is not field repairable If replacing the indoor blower motor or blower wheel is necessary placement is critical The blower wheel must be centered in the blower housing as shown in Figure 10 When replacing the indoor blower motor the set screw must be aligned and tightened with the motor shaft as shown in Figure 11 Secondary L...

Page 16: ... If 24 volts is not present problem may be up stream of plug P49 Proceed to test 4 Multi Meter set to VAC 12 0 12 0 24 Multi Meter set to VAC problem is with the harness If voltage is not present problem may be may be with the integrated control Check for 120 volts across terminals CIRC and Neutrals on the integrated control If voltage is present problem is with the harness If voltage is not prese...

Page 17: ...connection Compounds used on gas piping threaded joints should be resistant to action of liquefied petroleum gases Testing Gas Piping If a flexible gas connector is required or allowed by the authority that has jurisdiction black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet CAUTION Placement Installation Make sure unit is installed in accordance with install...

Page 18: ...re to time in Table 7 If manifold pressure matches Table 9 and rate is incorrect check gas orifices for proper size and restriction Remove temporary gas meter if installed NOTE To obtain accurate reading shut off all other gas appliances connected to meter Capacity Seconds for One Revolution Natural LP 1 cu ft Dial 2 cu ft Dial 1 cu ft Dial 2 cu ft Dial 45 80 160 200 400 70 55 110 136 272 90 41 82...

Page 19: ...50 0 034 10 0 11K50 0 034 10 0 10 0 070 Nat 4 5 10 0 No Change 0 0625 3 5 No Change 0 0625 3 3 11K45 0 032 3 5 LP Propane 11 0 13 0 11K50 0 034 10 0 11K50 0 034 10 0 10 0 090 Nat 4 5 10 0 No Change 0 0625 3 5 No Change 0 0625 3 3 11K45 0 032 3 5 LP Propane 11 0 13 0 11K50 0 034 10 0 11K50 0 034 10 0 10 0 110 Nat 4 5 10 0 No Change 0 0625 3 5 No Change 0 0625 3 3 74W60 0 60 w c 11K45 0 032 3 5 LP P...

Page 20: ...cates a poor or partial ground Compare the readings to Table 10 If the readings exceed the maximum shown in Table 10 make repairs before operating the furnace 2 In addition measure the AC voltage from Line Hot to Line Neutral spade terminals on the integrated control See Figure 16 This voltage should be in the range of 97 to 132 VAC Furnace Status Measurement VAC Expected Maximum Power On Furnace ...

Page 21: ...le in supply and return air plenums Insert manometer hose flush with inside edge of hole or insulation Seal around the hose with permagum Connect the zero end of the manometer to the discharge supply side of the system On ducted systems connect the other end of manometer to the return duct as above 3 With only the blower motor running and the evaporator coil dry observe the manometer reading Adjus...

Page 22: ...lower assembly and clean the housing blower wheel and blower motor if necessary The blower motors are prelubricated for extended bearing life No further lubrication is needed 7 Inspect the combustion air inducer and clean if necessary 8 Evaluate the heat exchanger integrity by inspecting the heat exchanger per the AHRI heat exchanger inspection procedure This procedure can be viewed at www ahrinet...

Page 23: ...ft side or right side of cabinet See Figure 19 9 Back wash using steam Begin from the burner opening on each clam Steam must not exceed 275 F 10 To clean burners run a vacuum cleaner with a soft brush attachment over the face of burners Visually inspect inside the burners and crossovers for any blockage caused by foreign matter Remove any blockage Figure 20 shows burner detail 11 To clean the comb...

Page 24: ... inducer burners manifold and gas valve retention rings cross over heat exchanger gasket collector box orifice plate internal flue pipe pressure switch combustion air inducer burners manifold and gas valve flue chase gasket ignitor rollout switch sensor Figure 20 Burner Combustion Air Inducer Assembly Heat Exchanger Removal ...

Page 25: ...ATING IF THE RESULTING TEMPERATURE RISE IS OUTSIDE OF THE RANGE SPECIFIED ON THE RATING PLATE R REQUIRED ON SOME OUTDOOR UNITS PARK TERMINALS ARE UNPOWERED TERMINALS ALL UNUSED MOTOR LEADS MUST BE WIRED TO A PARK TERMINAL USE COPPER CONDUCTORS ONLY L13 POWER CHOKE NOT USED ON ALL MOTORS Figure 21 Wiring Diagram ...

Page 26: ...GAS VALVE OFF COMBUSTION AIR INDUCER ON INDOOR BLOWER ON HEATING SPEED LED FLASHES CODE 11 PRESSURE SWITCH CLOSED GAS VALVE OFF COMBUSTION AIR INDUCER OFF INDOOR BLOWER OFF WITH DELAY Sequence holds until pressure switch opens or thermostat resets control NO NO YES YES IS VOLTAGE ABOVE 70 VOLTS LED FLASHES CODE 13 LOW LINE VOLTAGE CONTROL WILL NOT RESPOND TO A CALL FOR HEATING UNTIL VOLTAGE RISES ...

Page 27: ... IS 60 MINUTE RESET PERIOD COMPLETE YES 4 SECONDS YES HAS CONTROL RESET IGNITION SEQUENCE FOUR TIMES FLAME SIGNAL 1 5 MICROAMPS OR GREATER YES YES YES ROLLOUT SWITCH CLOSED LED FLASHES CODE 8 ROLLOUT SWITCH OPEN GAS VALVE POWER OFF COMBUSTION AIR INDUCER POWER ON INDOOR BLOWER ON SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET AND MAIN POWER IS INTERRUPTED OR THERMOSTAT IS CYCLED OFF ON FOR 1 SEC MIN...

Page 28: ...RED CONTINUOUSLY IS ROLLOUT SWITCH CLOSED LED SLOW FLASH RATE REMAINS UNCHANGED THROUGHOUT COOLING CYCLE THERMOSTAT CALLS FOR COOLING COMPRESSOR CONTACTOR AND SYSTEM FAN ENERGIZED WITH 2 SECOND DELAY COOLING SPEED COMPRESSOR OFF THERMOSTAT OPENS SYSTEM FAN AND EAC TERM OFF WITH 45 SECOND DELAY NO NO LED FLASHES CODE 8 ROLLOUT SWITCH OPEN GAS VALVE OFF COMBUSTION AIR INDUCER ON INDOOR BLOWER ON SEQ...

Page 29: ...RMOSTAT OPENS SYSTEM FAN SWITCHED TO COOL SPEED EAC TERM REMAINS ON THERMOSTAT OPENS MANUAL FAN SELECTION MADE AT THERMOSTAT CONTROL G ENERGIZES SYSTEM FAN AT FAN SPEED EAC TERM ENERGIZED NO YES YES NO SYSTEM FAN SWITCHES TO HEAT SPEAD AFTER 30 SECOND DELAY EAC AND HUM TERMINALS REMAIN ON SYSTEM FAN CONTINUES FAN SPEED WITHOUT INTERRUPTION EAC TERMINAL REMAIN ON HUM TERMINALS ARE ENERGIZED WITH CO...

Page 30: ...Printed in the U S A All specifications and illustrations subject to change without notice and without incurring obligations ...

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