GC9C96 Service Manual

ManualsBrandsGoodman ManualsFurnacesGC9C96 - 100k BTU - Gas Furnace - 96% AFUE

Service and Troubleshooting

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RS6612020

June 2021

is a registered trademark of Maytag Corporation or its related companies and is used under license.

TABLE OF CONTENTS

IMPORTANT INFORMATION ............................................ 2

PRODUCT IDENTIFICATION ........................................... 4

SYSTEM OPERATION ...................................................... 5

SCHEDULED MAINTENANCE ....................................... 18

SERVICING ..................................................................... 22

CHECKING VOLTAGE .............................................. 23

CHECKING WIRING .................................................. 23

CHECKNG THERMOSTAT, WIRING ........................ 23

CHECKING TRANSFORMER AND CONTROL

CIRCUIT ...................................................................... 23

CHECKING AIR CIRCULATOR BLOWER MOTOR 24

CHECKING DUCT STATIC ........................................ 24

CHECKING TEMPERATURE RISE .......................... 25

CHECKING PRIMARY LIMIT CONTROL ................. 25

CHECKING AUXILIARY LIMIT CONTROL ............... 26

CHECKING FLAME ROLLOUT CONTROL ............. 27

INDUCED DRAFT BLOWER MOTOR ...................... 27

CECKING GAS VALVE (REDUNDANT) ................... 27

CHECKING MAIN BURNERS ................................... 28

CHECKING ORIFICES .............................................. 28

CHECKING GAS PRESSURE .................................. 28

CHECKING HOT SURFACE IGNITOR ..................... 30

CHECKING FOR FLASHBACK ................................. 30

CHECKING PRESSURE SWITCH............................ 30

HIGH ALTITUDE APPLICATION ............................... 31

CHECKING FOR DELAYED IGNITION .................... 31

CHECKING INTERGRATED IGNITION CONTROL

BOARDS ..................................................................... 31

CHECKING FLAME SENSOR ................................... 32

TROUBLESHOOTING CHART ....................................... 33

WIRING DIAGRAMS ....................................................... 37

Pride and workmanship go into every product to provide

our customers with quality products. It is possible, however,

that during its lifetime a product may require service.

Products should be serviced only by a qualied service

technician who is familiar with the safety procedures

required in the repair and who is equipped with the proper

tools, parts, testing instruments and the appropriate service

manual. 

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Summary of content (38 pages)

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Service and Troubleshooting Goodman® Brand GM9C96/GC9C96 & Amana® Brand AM9C96/AC9C96 Two Stage Furnace with Nine speed ECM Motor Pride and workmanship go into every product to provide our customers with quality products. It is possible, however, that during its lifetime a product may require service.
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IMPORTANT INFORMATION IMPORTANT NOTICES FOR CONSUMERS AND SERVICERS RECOGNIZE SAFETY SYMBOLS, WORDS AND LABELS Pride and workmanship go into every product to provide our customers with quality products. It is possible, however, that during its lifetime a product may require service.
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IMPORTANT INFORMATION CO can cause serious illness including permanent brain damage or death. B10259-216 Advertencia especial para la instalación de calentadores ó manejadoras de aire en áreas cerradas como estacionamientos ó cuartos de servicio. Las emisiones de monóxido de carbono pueden circular a través del aparato cuando se opera en cualquier modo. El monóxido de carbono puede causar enfermedades severas como daño cerebral permanente ó muerte.
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NOMENCLATURE PRODUCT IDENTIFICATION The model and manufacturing number are used for positive identification of component parts used in manufacturing. Please use these numbers when requesting service or parts information. A 1 Brand G - Goodman V - GMC C 4 8 5 0 6 0 7 6 8 0 9 3 10 B 11 N 12 A 13 A 14 Major Revision A - Initial Release B - 1st Revision Nox N = > 40 NG/J NOx X = < 40 NG/J NOx U = < 14NG/J NOx Cabinet Width A - 14" B - 17.5" C - 21" D - 24.
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SYSTEM OPERATION Introduction This is a Category lV furnace. This furnace uses a pressurized venting system and must be installed per National and local codes requirements and the installation manual that was shipped with the furnace. Return any old or new controls to their containers before touching any ungrounded object. Product Application This product is designed for use as a residential home gas furnace.
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SYSTEM OPERATION *M9C96 M INIMUM CLEARANCES TO COMBUSTIBLE M ATERIALS POSITION*S IDES REAR FRONTB OTTOMF LUET OP Upflow 0" 0" 1" C0 "1 " Horizontal 6" 0" 1" C0 "6 " *C9C96 M INIMUM CLEARANCES TO COMBUSTIBLE M ATERIALS POSITION*S IDES Counterflow0 "0 Horizontal • • 6" REAR "1 0" FRONTB OTTOMF "N C0 1" LUET C0 OP " "6 " C = If placed on combustible floor, floor MUST be wood only. NC = For installation on non-combustible floors only.
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CUT HERE SYSTEM OPERATION AIR DISCHARGE Side Return Duct Connection Bottom Return Duct Connection Figure 10 UPFLOW UPRIGHT 1. Remove screws from the vent flange. 2. Remove the internal elbow and vent pipe 3. Cut 2 1/2” from the flange . 4. Remove cabinet plug adjacent to inducer outlet and install an original cabinet vent hole. 5. Install RF000142 coupling on inducer outlet. 6. Install flanged vent section removed in step 2 and secure with clamps. 7.
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SYSTEM OPERATION Propane Gas and/or High Altitude Installations WARNING WARNING IN UPRIGHT UPFLOW INSTALLATIONS, THE DRAIN TRAP MUST BE MOUNTED ON THE OPPOSITE SIDE OF THE UNIT FROM THE JUNCTION BOX. THIS WILL POSSIBLE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH MAY OCCUR IF THE CORRECT CONVERSION KITS ARE NOT INSTALLED. THE APPROPRIATE KITS MUST BE APPLIED TO INSURE SAFE AND PROPER FURNACE OPERATION.
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SYSTEM OPERATION amount of air into the burner. This may cause incomplete combustion, flashback, and possible yellow tipping. In some areas the gas supplier may artificially derate the gas in an effort to compensate for the effects of altitude. If the gas is artificially derated, the appropriate orifice size must be determined based upon the BTU/ft3 content of the derated gas and the altitude. Refer to the National Fuel Gas Code, NFPA 54/ANSI Z223.
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SYSTEM OPERATION GAS PIPING CHECKS Before placing unit in operation, leak test the unit and gas connections. 5 to 15 PSIG (20 PSIG Max.) First Stage Regulator Continuous 11" W.C. WARNING TO AVOID THE POSSIBLITY OF EXPLOSION OR FIRE, NEVER USE A 200 PSIG Maximum MATCH Second Stage Regulator OR OPEN FLAME TO TEST FOR LEAKS. Check for leaks using an approved chloride-free soap and water solution, an electronic combustible gas detector, or other approved testing methods.
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SYSTEM OPERATION WARNING IF THE INFORMATION IN THESE INSTRUCTIONS IS NOT FOLLOWED EXACTLY, A FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE. – DO NOT STORE OR USE GASOLINE OR OTHER FLAMMABLE VAPORS AND LIQUIDS IN THE VICINITY OF THIS OR ANY OTHER APPLIANCE. – WHAT TO DO IF YOU SMELL GAS: • DO NOT TRY TO LIGHT ANY APPLIANCE. • DO NOT TOUCH ANY ELECTRICAL SWITCH; DO NOT USE ANY PHONE IN YOUR BUILDING. • IMMEDIATELY CALL YOUR GAS SUPPLIER FROM A NEIGHBOR’S PHONE.
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SYSTEM OPERATION WARNING IN 90% FURNACE UPRIGHT UPFLOW INSTALLATIONS, THE DRAIN TRAP MUST BE MOUNTED ON THE OPPOSITE SIDE OF THE UNIT FROM THE JUNCTION BOX. are built into the furnace to allow use with most cooling equipment. Consult the wiring diagram located in this manual, the installation manual, or on the blower door for further details of 115 Volt and 24 Volt wiring. THIS WILL REDUCE THE RISK OF WATER REACHING THE JUNCTION BOX IN THE EVENT OF A BLOCKED DRAIN CONDITION.
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SYSTEM OPERATION • Fixed time options are expressed in minutes on the display as: 10 20 30 60. • If AUt (Automatic) is selected, the actual timing for the transition to 2nd stage heat will be calculated by the control board based on length of run time of previous heating cycles (duty cycle). • Press the center switch to save the selection. In Auto mode, the transition to 2nd stage heat will vary between 1 to 12 minutes.
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SYSTEM OPERATION inside the furnace junction box. The integrated control module humidifier terminal (HUM H) is energized with 115 volts whenever the induced draft blower is energized. The integrated control module electronic air cleaner terminal (EAC H) is energized with 115 volts whenever the circulator blower is energized. This terminal can also be used to provide 115 volt power to a humidifier transformer. The remaining primary transformer wire would be connected to the Line N on the control board.
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SYSTEM OPERATION • • • • • The 2nd stage gas heat speed of the indoor blower is energized When the thermostat is satisfied: The gas valve is de-energized. The inducer remains energized for the post purge period (15 seconds). The indoor blower runs for the selected off delay period (90 seconds by default, adjustable from 30 – 180 seconds). Call for 2nd Stage Heat During 1st Stage Heat Operation • The control board receives a 24 VAC signal on the W2 terminal. • The inducer motor is enabled at high speed.
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SYSTEM OPERATION Cooling Mode Speed Selection To change the main blower speed in COOLING mode, follow the following steps: 1. Press the left or right switch until LED displays “AC1 “(for single stage COOLING) or “AC2 “(for two-stage COOLING). Press the center switch and LED will display the selected speed number as Fxx (xx: Blower speed number from 1 to 9). 2. The control will rotate available speed number every time left/right switches are pressed.
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SYSTEM OPERATION Upflow Models Minimum Recommended Filter Size *0403A* 1 - 16 X 25 Side or 1 - 14 X 24 Bottom Return *0603A* 1 - 16 X 25 Side or 14 X 24 Bottom Return *0603B* 1 - 16 X 25 Side or Bottom Return *0803B* 1 - 16 X 25 Side or Bottom Return *0804B* 1 - 16 X 25 Side or Bottom Return *0804C* 1 - 16 X 25 Side or Bottom Return *0805C* 1 - 16 X 25 Side or Bottom Return¹ *0805D* 2 - 16 X 25 Side or 1 - 20 X 25 Bottom Return¹ *1004C* 2 - 16 X 25 Side or 1 - 20 X 25 Bottom Return *1005C* 2 - 16 X 25 Side
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SCHEDULED MAINTENANCE WARNING Improper filter maintenance is the most common cause of inadequate heating or cooling performance. Filters should be cleaned (permanent) or replaced (disposable) every two months or as required. It is the owner’s responsibility to keep air filters clean. When replacing a filter, it must be replaced with a filter of the same type and size. HIGH VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT.
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SCHEDULED MAINTENANCE Periodically during the heating season make a visual check of the burner flames. Turn the furnace on at the thermostat. Wait a few minutes since any dislodged dust will alter the normal flame appearance. Flames should be stable, quiet, soft and blue with slightly orange tips. They should not be yellow. They should extend directly outward from the burner ports without curling downward, floating or lifting off the ports. Check the Burner Flames for: 1. Stable, soft and blue. 2.
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SCHEDULED MAINTENANCE 1 1 In this example we are using the one cubic foot dial on the gas meter CUBIC FEET One TABLE 1 4. Using Table 2 below, find the number of seconds it took for the dial to make a full revolution. To the right of that number of seconds and below the Size of Test Dial (selected in step 3 and shown in Table 1) will be the Cubic Feet per Hour (CFH).
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SCHEDULED MAINTENANCE 6. Check with your local utility for actual BTU content (caloric value) of natural gas in the area (the average is 1025 BTU’s). 7. Use this formula to calculate the BTU/HR input (See BTU/HR Calculation Example): Cubic Feet per Hour (CFH) x BTU content of your natural gas = BTU/HR input 8. Should the figure you calculated not fall within five (5) percent of the nameplate rating of the unit, adjust the gas valve pressure regulator or resize orifices.
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SERVICING As more and more electronic's are introduced to the Heating Trade, Polarization of incoming power and phasing of primary to secondary voltage on transformers becomes more important. INCOMING POWER 120.00 0.00 Polarization has been apparent in the Appliance industry since the introduction of the three prong plug, however, the Heating Industry does not use a plug for incoming power, but is hard wired.
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SERVICING CHECKING VOLTAGE CHECKING THERMOSTAT, WIRING WARNING WARNING HIGH VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING OR CHANGING ANY ELECTRICAL WIRING. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH. 1. Remove cover from the Junction Box and gain access to incoming power lines. With Power ON: WARNING LINE VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING. 1.
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SERVICING 2. Remove the thermostat low voltage wires at the furnace integrated control module terminals. With Power On (and Door Interlock Switch closed): WARNING LINE VOLTAGE NOW PRESENT 3. Use a voltmeter, check voltage across terminals R and C. Must read 24 VAC. 4. No voltage indicates faulty transformer, open fuse, bad wiring, bad splice, or open door interlock switch. 5. Check transformer primary voltage at incoming line voltage connections, fuse, splices, and blower door interlock switch. 6.
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SERVICING CHECKING TEMPERATURE RISE The more air (CFM) being delivered through a given furnace, the less the rise will be; so the less air (CFM) being delivered, the greater the rise. The temperature rise should be adjusted in accordance to a given furnace specifications and its external static pressure. An incorrect temperature rise may result in condensing in or overheating of the heat exchanger. An airflow and temperature rise table is provided in the blower performance specification section.
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SERVICING 3. With an ohmmeter, test between these two terminals as shown in the following drawing. The ohmmeter should read continuous unless heat exchanger temperature is above limit control setting. If not as above, replace the control. WARNING HIGH VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.  1. Remove blower compartment door to gain access to the auxiliary. 2.
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SERVICING CHECKING FLAME ROLLOUT CONTROL A temperature activated manual reset control is mounted to the manifold assembly as shown in the following illustration. FLAME ROLLOUT SWITCHES INDUCED DRAFT BLOWER MOTOR WARNING HIGH VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH. 1. Remove burner compartment door to gain access to the induced draft blower motor. 2.
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SERVICING CHECKING MAIN BURNERS The main burners are used to provide complete combustion of various fuels in a limited space, and transfer this heat of the burning process to the heat exchanger. Proper ignition, combustion, and extinction are primarily due to burner design, orifice sizing, gas pressure, primary and secondary air, vent and proper seating of burners. 1. 2. Check orifice visually for distortion and/or burrs. Check orifice size with orifice sizing drills.
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SERVICING Manometer Hose High Fire Regulator Adjust Regulator Vent 3.5 High Fire Coil Coaxial Coil Terminal (HI) Terminal (M) Common On/Off Switch Terminal(C) Manometer . White-Rodgers Model 36J54 Connected to Manometer White-Rodgers Model 36J54 Connected to Manometer Measuring Inlet Gas Pressure (Alt. Method) 1. Turn OFF gas to furnace at the manual gas shutoff valve external to the furnace. 2.
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SERVICING 12. Remove the manometer hose from the hose barb fitting or outlet pressure tap. 13. Replace outlet pressure tap: White-Rodgers 36J54 valve: Turn outlet pressure test screw in to seal pressure port (clockwise, 7 in-lb minimum). 14. Turn on electrical power and gas supply to the system. 15. Close thermostat contacts “R” and “W1/W2” to energize the valve. Manifold Gas Pressure Gas Range Natural Low Stage 1.6 - 2.2" w .c. High Stage 3.2 - 3.8" w .c. Propane Low Stage 5.7 - 6.3" w .c. High Stage 9.
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SERVICING and the ohm meter should show a complete circuit across the pressure switch. If the switch is not closed, compare the negative pressure to the closing point specified for the particular switch. Either the switch is defective or the inducer / venting system is inadequate. INDUCED DRAFT BLOWER PRESSURE SWITCH * * * M 1 P O F F 3 C PRESSURE SWITCH HOSE OPEN TO ATMOSPHERE * 2 ON * * * COIL COVER PRESSURE SWITCH 1/4" TEE -. INDUCED DRAFT BLOWER 2.
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SERVICING CHECKING FLAME SENSOR A flame sensing device is used in conjunction with the ignition control module to prove combustion. If proof of flame is not present the control will de-energize the gas valve and “retry” for ignition or lockout. WARNING HIGH VOLTAGE DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH. Flame current can be measured by: 1. Putting a D.C.
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IMPORTANT INFORMATION 2 Stage Status Codes Menu Description LED Display Main Menu Option Menu   xx xx  CR Number Reset to Factory Default  yes, no Blower Speed for Continous Fan Mode  xx Blower Speed for 1st Stage Compressor Mode  xx Blower Speed for 2nd Stage Compressor Mode  xx Cool On Delay  Delay, Seconds Active Alarm menu Last 6 Faults Code Release Number Cool Off Delay  Delay, Seconds Blower Speed for 1st Stage Gas Heat Mode  xx Blower Sp
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IMPORTANT INFORMATION 2 Stage Status Codes Mode Idle 34 Main Menu Continous Fan   Compressor Cooling, Low Stage  Compressor Cooling, High Stage  Gas heat, Low Stage  Gas heat, High Stage  OEM test Mode 
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IMPORTANT INFORMATION 2 Stage Troubleshooting Codes TROUBLESHOOTING CHART Symptom LED Status Fault Description Corrective Actions Normal operation  Normal operation None Locate and correct gas interruption Furnace fails to operate  Replace or realign igniter Furnace lockout due to an excessive number Check flame sense signal, clean sensor if coated or of ignition “retries” (3 total) oxidized Failure to establish flame Check flue piping for blockage, proper length, elbows, and Loss of flame a
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IMPORTANT INFORMATION 2 Stage Troubleshooting Codes Symptom LED Status TROUBLESHOOTING CHART Fault Description Corrective Actions Flame sense micro amp signal is minimal Normal furnace operation  Flame sensor is coated/oxidized Flame sensor incorrectly positioned in burner fame Lazy burner flame due to improper gas pressure or combustion air Problem with igniter circuit Furnace fails to operate  Improperly connected or shorted igniter Poor unit ground Igniter relay fault on integrated control
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WIRING DIAGRAMS *M9C96/*C9C96 RD 3 C 2 TWO STAGE PM GAS VALVE (WHITE RODGERS) C NO NO PU C GY DISCONNECT GY NO FLAME SENSOR JUNCTION BOX GND GND NEUTRAL LINE YL HUM-OUT PK IND HI BK BK FS RD BR PU 3 10 7 4 1 12 9 6 YL PU 11 8 5 2 SW3 PK RIGHT COM BR LEFT T5 RD BL CENTER T4 RD 3 T3 24V THERMOSTAT CONNECTIONS N.E.C.
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CUSTOMER FEEDBACK We are very interested in all product comments. Please fill out the feedback form on one of the following links: Goodman® Brand Products: (http://www.goodmanmfg.com/about/contact-us). Amana® Brand Products: (http://www.amana-hac.com/about-us/contact-us). You can also scan the QR code on the right for the product brand you purchased to be directed to the feedback page. ® 38 GOODMAN® BRAND is a registered trademark of Maytag Corporation or its related companies and is used under license.