CONQUEST 90 - Main Burner

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1,
GAS VALVE OPENS AND
MAIN BURNER LIGHTS
YES
•
MAIN BURNER
REMAINS POWERED
AND LIT
REPLACE IFC IF
WIRING TO VALVE IS OK
FLOW THAU VALVE
REPLACE IGNITER I
SYSTEM WILL ATTEMPT TO LIGHT 4 TIMES.
VOLTAGE IS PRESENT AT THE VALVE FOR
FOR 90+ MODELS ONLY,
ONLY 8 SECONDS DURING EACH TRIAL FOR
MAKE SURE DRAIN
IGNITION (SYSTEM WILL GO INTO
A 1-HOUR
NO
PRESSURE SWITCH
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NO _
LOCKOUT AFTER 4 TRIES). THE BLOWER AND
-
BETWEEN IFC AND GAS
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IDM WILL RUN 180 SEC. IF THE SECOND
VALVE IS CLOSED
IGNITION TRIAL FAILS TO SENSE FLAME.
YES
+NO
• CHECK FOR 24 VAC ACROSS THE VALVE
AND VALVE TERMINALS ON THE IFC
REPLACE DRAIN
f YES
PRESSURE SWITCH
• CHECK IGNITER POSITION.
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• CHECK FOR GAS FLOW TO AND FROM VALVE.
f NO
REPLACE VALVE IF NO
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NOTE: IF IFC GOES INTO LOCKOUT WAIT 30 SECONDS THEN
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NO
-
-
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YES
1;
INDOOR BLOWER MOTOR
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NO
RESET SYSTEM
• CHECK POLARITY OF 115 VAC SUPPLY
• CHECK CONTINUITY OF GROUND WIRE
• CHECK INSULATION ON IGNITER LEADS
• CHECK FLAME SENSE CURRENT (YELLOW LED)
LED IS ON IF FLAME CURRENT IS GOOD,
IT FLASHES IF CURRENT IS MARGINAL.
• TURN POWER OFF TO UNIT
• CLEAN FLAME SENSOR WITH STEEL WOOL IF LED FLASHES
• RESTORE POWER TO UNIT
• IF CHECKS ARE OK, REPLACE IFC
•CHECK FOR 115 VAC ACROSS BLOWER
STARTS 20 SECONDS MOTOR AND BLOWER MOTOR TERMINALS
-
AFTER MAIN GAS VALVE OPENS (HEAT AND NEUTRAL) ON IFC
YES
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+YES
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SYSTEM RUNS
UNTIL CALL FOR
HEAT ENDS
YES
1
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TURN THERMOSTAT TO OFF
VALVE SHUTS OFF
FLAME GOES OUT
YES
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DRAFT MOTOR STOPS AFTER 5 SEC.
,vEs
INDOOR BLOWER MOTOR
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-
REPLACEIFC
NO
• CHECK FOR OPEN LIMIT.
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I
STOPS AFTER
90/120/160/180 SECONDS
YES
~REPLACE IFC IF
NO WIRING TO BLOWER
MOTOR IS OK
REPLACE BLOWER MOTOR
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NO
-
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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 FLAME SENSE CURRENT
• CHECK FOR EXCESSIVE HEAT AT IGNITER BASE, (TEMP.
ABOVE 1000 F (538 C) CAUSES SHORT TO GROUND)
• TURN POWER OFF TO UNIT.
• CLEAN FLAME SENSOR WITH STEEL WOOL
• RESTORE POWER TO UNIT.
• IF CHECKS ARE OK, REPLACE IFC
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NO
• CHECK FOR PROPER THERMOSTAT OPERATION.
-
-
• REMOVE VALVE LEAD AT IFC
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IF VALVE CLOSED, RECHECK THERMOSTAT AND
WIRING.IF NOT, REPLACE VALVE.
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-
NO
• CHECK FOR OPEN LIMIT.
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REPLACEIFC
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TROUBLESHOOTING ENDS
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REPEAT PROCEDURE UNTIL TROUBLEFREE
OPERATION IS OBTAINED.
92-22744-10-03
NOTE:
STATIC DISCHARGE CAN DAMAGE INTEGRATED FURNACE CONTROL (IFC)
• "OK" LED BLINKS TO INDICATE EXTERNAL FAULTS:
(1) BLINK FOLLOWED BY A 2 SEC. PAUSE - 1 HOUR LOCKOUT
{2) BUNKS FOLLOWED BY A 2 SEC. PAUSE - PRESSURE SWITCH IS OPEN
{3) BUNKS FOLLOWED BY
A 2 SEC. PAUSE LIMIT SWITCH IS OPEN
(4) BUNKS FOLLOWED BY A 2 SEC. PAUSE - PRESSURE SWITCH CLOSED
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