37
Troubleshooting Chart 3
CHECK FOR VAC
BETWEEN TERMINALS 1 AND 3
AT CONNECTOR CN4 ON IBC
NO
NO
BLOWER STARTS
REPLACE IBC
CHART 1
OPEN
PURGE LIGHT ON?
NO
YES
IBC WAITS UP TO 5
MINUTES FOR NORMALLY
OPEN AIR
PRESSURE SWITCH
CONTACTS TO CLOSE,
INDICATING BLOWER
SUCTION IS
PRESENT
YES
CHECK FOR 120 VAC AT
BLOWER LEADS ON WIRING
HARNESS
YES
REPAIR/REPLACE
BLOWER
NO
REPAIR/REPLCE
WIRING FROM IBC
TO BLOWER
PRESSURE SWITCH
CONTACTS
OPEN
ARE VENT PIPE AND AIR
INTAKE PIPE CLEAR
(NO BLOCKAGE)
NO
CLEAN OUT VENT PIPE
AND/OR AIR INTAKE PIPE.
CHECK FOR SAGS OR
LOW SPOTS WHERE
CONDENSATE MAY
PUDDLE AND BLOCK
THE VENT
YES
CHECK AIR
PRESSURE SWITCH PER
INSTRUCTIONS ON
FOLLOWING PAGES. ARE
SAMPLING LINES CLEAR
AND CONNECTED
PROPERLY?
NO
CLEAN OUT SAMPLING
LINES OR REPLACE
DEFECTIVE SWITCH
YES
CHECK FLUE PASSAGES
IN BOILER PER
"MAINTENACE AND
CLEANING". ARE FLUE
PASSAGES IN BOILER CLEAN?
NO
CLEAN BOILER FLUE
PASSAGES PER
MAINTENANCE AND
CLEANING INSTRUCTIONS
YES
CHECK DRAFT INDUCER
MOTOR RPM. IS IT
3400-3600?
NO
REPLACE
BLOWER
YES
CHECK FOR BROKEN OR
LOOSE IMPELLER ON DRAFT
INDUCER AND REPLACE
BLOWER IF FOUND TO
BE BROKEN OR LOOSE
YES
15 SECOND PRE PURGE COMPLETE.
PURGE LIGHT IS OFF. SIMULTANEOUSLY
IGNITOR LIGHT IS ON AS IGNITOR CIRCUIT
IS ENERGIZED.
YES
CHART 4
NO
REPLACE IBC
15 - TROUBLESHOOTING
