5 69-0685
FIG. 3—S9201A1010 TROUBLESHOOTING GUIDE.
NO
YES
REPLACE BLOWER MOTOR
YES
REPLACE GAS CONTROL
NO
NO
REPLACE IFC IF WIRING TO IGNITER IS OK
YES
NO
CHECK LINE VOLTAGE POWER
CHECK LOW VOLTAGE TRANSFORMER
PWR LIGHT ON
YES
YES
NO
IGNITER WARMS UP
AND GLOWS RED
(36 SECOND WARMUP)
¥
¥
30 SEC PREPURGE
NO
REPLACE IFC
YES
NO
YES
NO
REPLACE SWITCH
REPLACE IFC IF WIRING TO
IDB MOTOR IS OK
REPLACE IDB MOTOR
START
SET THERMOSTAT TO
CALL FOR HEAT
SET FAN SWITCH TO AUTO
¥ CHECK LIMITS (CLOSED)
¥ CHECK WIRING
¥ CHECK AIR PROVING SWITCH (OPEN)
¥ CHECK FOR 120 VAC TO IDB MOTOR
OK LIGHT ON
YES
¥ CHECK FOR BLOCKED VENT
¥ CHECK AIR PROVING SWITCH (CLOSED)
¥ CHECK WIRING TO IGNITER
¥ CHECK FOR 120 VAC AT IGNITER
¥ TERMINALS AND AT IFC TERMINALS
REPLACE IGNITER
NO
MAIN BURNER
LIGHTS
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
NO
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
NO
MAIN BURNER
REMAINS
POWERED AND LIT
YES
YES
YES
YES
NO
NO
INDOOR BLOWER
MOTOR STARTS
AFTER 30 SECONDS
¥ CHECK FOR 120 VAC ACROSS BLOWER
¥ MOTOR AND BLOWER MOTOR
¥ TERMINALS ON IFC
REPLACE IFC IF WIRING TO
BLOWER MOTOR IS OK
M890
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
NO
SYSTEM RUNS
UNTIL CALL FOR
HEAT ENDS
YES
YES
¥ 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
NO
YES
INDUCED DRAFT
MOTOR STARTS
SET THERMOSTAT TO OFF,
GAS CONTROL CLOSES,
FLAME OFF
NO
INDOOR BLOWER
MOTOR STOPS AFTER
90/45/60/75 SECS
YES
TROUBLESHOOTING
ENDS
¥ CHECK FOR OPEN LIMIT. REPLACE IFC
REPEAT PROCEDURE UNTIL TROUBLEFREE
OPERATION IS OBTAINED
IFC = Integrated Furnace Control
IDB = Induced Draft Blower
KEY:
NOTE: STATIC DISCHARGE CAN DAMAGE IFC
WARNING
ELECTRICAL SHOCK HAZARD
MAY CAUSE SERIOUS INJURY OR DEATH
Dangerous line voltage is exposed during troubleshooting.
Disconnect power before touching control. Service must be
by trained, experienced service technician.
REPLACE SWITCH
¥ CHECK IGNITER POSITION
¥ CHECK FOR GAS FLOW TO AND FROM
¥ GAS CONTROL
REPLACE IFC IF WIRING TO
GAS CONTROL IS OK
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