UTICA BOILERS UB90-200 Installation, Operation & Maintenance Manual page 37

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