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START
SET THERMOSTAT TO
CALL FOR HEAT
SET FAN SWITCH TO AUTO
YES
INDUCED DRAFT
NO
MOTOR STARTS
YES
30 SEC PREPURGE
YES
IGNITER WARMS UP
AND GLOWS RED
NO
(36 SECOND WARMUP)
YES
MAIN BURNER
NO
LIGHTS
YES
MAIN BURNER
REMAINS
NO
POWERED AND LIT
YES
INDOOR BLOWER
MOTOR STARTS
NO
AFTER 30 SECONDS
YES
SYSTEM RUNS
UNTIL CALL FOR
NO
HEAT ENDS
YES
SET THERMOSTAT TO OFF,
GAS CONTROL CLOSES,
NO
FLAME OFF
YES
INDOOR BLOWER
MOTOR STOPS AFTER
NO
90/45/60/75 SECS
YES
TROUBLESHOOTING
ENDS
ELECTRICAL SHOCK HAZARD
MAY CAUSE SERIOUS INJURY OR DEATH
PWR LIGHT ON
YES
OK LIGHT ON
YES
¥ CHECK LIMITS (CLOSED)
¥ CHECK WIRING
¥ CHECK AIR PROVING SWITCH (OPEN)
¥ CHECK FOR 120 VAC TO IDB MOTOR
YES
REPLACE IDB MOTOR
¥ CHECK FOR BLOCKED VENT
¥ CHECK AIR PROVING SWITCH (CLOSED)
¥ CHECK WIRING TO IGNITER
¥ CHECK FOR 120 VAC AT IGNITER
¥
TERMINALS AND AT IFC TERMINALS
YES
REPLACE IGNITER
System will attempt to light 5 times (30 second delay between tries). Voltage is present at the valve
for only 9 seconds during each trial for ignition. System will lock out after 5 tries.
¥ CHECK FOR 24 VAC ACROSS THE P1-2 AND P1-4 TERMINALS ON THE IFC
¥ CHECK IGNITER POSITION
¥ CHECK FOR GAS FLOW TO AND FROM
¥
GAS CONTROL
YES
REPLACE GAS CONTROL
NOTE: If IFC goes into lockout wait 30 seconds then reset system.
¥ CHECK LINE VOLTAGE POLARITY
¥ CHECK CONTINUITY OF GROUND WIRE
¥ CHECK INSULATION ON IGNITER LEADS
¥ CHECK INSULATION ON SENSOR LEADS
¥ CHECK SENSOR POSITION
¥ IF CHECKS ARE OK, REPLACE IFC
¥ CHECK FOR 120 VAC ACROSS BLOWER
¥
MOTOR AND BLOWER MOTOR
¥
TERMINALS ON IFC
YES
REPLACE BLOWER MOTOR
NOTE: If IFC goes into lockout wait 30 seconds then reset system.
¥ CHECK CONTINUITY OF GROUND WIRE. NOTE: IF GROUND IS POOR OR ERRATIC, SHUTDOWN MAY
¥
OCCUR OCCASIONALLY EVEN THOUGH OPERATION IS NORMAL AT THE TIME OF CHECKOUT.
¥ CHECK FOR EXCESSIVE HEAT AT IGNITER BASE. TEMPERATURE ABOVE 1000F (538 C) CAUSES
¥
SHORT TO GROUND
¥ IF CHECKS ARE OK, REPLACE IFC
¥ CHECK FOR PROPER TEMPERATURE CONTROLLER OPERATION
¥ REMOVE GAS CONTROL LEAD AT IFC. IF GAS CONTROL CLOSES, RECHECK TEMPERATURE
¥
CONTROLLER AND WIRING. IF NOT, REPLACE GAS CONTROL
¥ CHECK FOR OPEN LIMIT. REPLACE IFC
REPEAT PROCEDURE UNTIL TROUBLEFREE
OPERATION IS OBTAINED
NOTE: STATIC DISCHARGE CAN DAMAGE IFC
FIG. 3—S9201A1010 TROUBLESHOOTING GUIDE.
WARNING
Dangerous line voltage is exposed during troubleshooting.
Disconnect power before touching control. Service must be
by trained, experienced service technician.
¥
NO
¥
REPLACE IFC
NO
NO
REPLACE SWITCH
NO
REPLACE IFC IF WIRING TO
IDB MOTOR IS OK
REPLACE SWITCH
NO
NO
REPLACE IFC IF WIRING TO IGNITER IS OK
REPLACE IFC IF WIRING TO
GAS CONTROL IS OK
REPLACE IFC IF WIRING TO
NO
BLOWER MOTOR IS OK
5
CHECK LINE VOLTAGE POWER
CHECK LOW VOLTAGE TRANSFORMER
NO
KEY:
IFC = Integrated Furnace Control
IDB = Induced Draft Blower
M890
69-0685
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