Heat Controller TGC Series Installation Instructions Manual page 48

FURNACE TROUBLESHOOTING GUIDE
(COMBINATION HEATING AND COOLING UNITS WITH DIRECT SPARK IGNITION)
START
SET THERMOSTAT TO
CALL FOR HEAT
SET FAN SWITCH TO AUTO
YES
INDUCED DRAFT BLOWER
MOTOR STARTS
YES
15 SECOND PREPURGE
YES
IGNITOR SPARKS
YES
MAIN BURNER LIGHTS
YES
48
WARNING
!
HAZARDOUS VOLTAGE DISCONNECT POWER BEFORE
LINE VOLTAGE CON-
SERVICING.
NECTIONS
SERVICE MUST BE BY A TRAINED,
QUALIFIED SERVICE TECHNICIAN.
• CHECK LINE VOLTAGE TO CONTROL BOARD
NO
• CHECK LOW VOLTAGE TRANSFORMER
• CHECK WIRING
• CHECK FOR 208-230 VAC TO IOM MOTOR
REPLACE INDUCED
DRAFT BLOWER
NO
• CHECK IGNITOR CABLE
• CHECK SPARK IGNITOR POSITION AND CONDITION
• IS NEGATIVE PRESSURE SWITCH CLOSED?
• CHECK FOR OPEN ROLL-OUT CONTROL
• CHECK FOR OPEN LIMIT
• CHECK IGNITION CONTROL CHASSIS GROUND WIRE
• CHECK WIRING
REPLACE IGNITION CON-
NOTE: THE SYSTEM WILL ATTEMPT TO LIGHT 3 TIMES WITH A 60 SECOND INTER-
PURGE BETWEEN TRIES. IF AFTER THE THIRD TIME THE BURNERS
DO NOT LIGHT, THE SYSTEM WILL LOCK OUT. IF THE UNIT IS EQUIPPED WITH
A UNITED TECH. OR JOHNSON CONTROLS IGNITION CONTROL, THE SYSTEM
WILL ATTEMPT TO LIGHT 3 TIMES EACH HOUR UNTIL THE BURNERS LIGHT OR
THE THERMOSTAT IS RESET.
NO
• CHECK INLET GAS PRESSURE
• CHECK 24 VOLTS TO GAS VALVE
• CHECK FOR GAS FLOW TO AND FROM VALVE
• CHECK BURNER CARRYOVER
REPLACE VALVE
FLOW CHART CONTINUED ON NEXT PAGE
NO
YES
YES
NO
YES
YES
NO
TROL
NO
YES
REPLACE INTEGRATED
CONTROL BOARD (IFC)
REPLACE IGNITOR/
CABLE ASSEMBLY
• CHECK NEGATIVE PRESSURE
SWITCH SENSING TUBE
• CHECK FOR EXHAUST
BLOCKAGE
NO
REPLACE NEGATIVE
PRESSURE SWITCH
CHECK FOR EXHAUST,
INTAKE OR HEAT
EXCHANGER BLOCKAGE
AND RESET CONTROL
REPLACE LIMIT
IF UNIT IS COLD
REPLACE INTEGRATED
CONTROL BOARD (IFC)
IF WIRING IS OK