UTICA BOILERS UB90-50 Installation, Operation & Maintenance Manual page 56

Troubleshooting Chart 5
CHART 4
YES
CHECK GAS LINES DOWNSTREAM OF GAS
IS GAS/VENTURI VALVE CORRECT SIZE?
CHECK FLUE PASSAGES IN BOILER PER
"MAINTENANCE AND CLEANING". ARE
FLUE PASSAGES IN BOILER CLEAN?
BLOCKAGE PER MAINTENANCE AND
CLEANING INSTRUCTIONS. ARE AIR
PASSAGES IN MIXER AND BURNER
CHECK AIR ORIFICE AT BURNER INLET
FOR CORRECT SIZE. SEE REPAIR PARTS
DIAGRAM. IS ORIFICE CORRECT SIZE?
DOES MAIN BURNER
RUN UNTIL CALL FOR
HEAT ENDS OR HI
LIMIT AQUASTAT
CONTACTS OPEN?
*
* IF THE ANSWER IS NO.
CHOOSE THE APPROPRIATE
PATH (#1, #2, OR #3) BASED ON
SYMPTOMS SHOWN.
CHART 6 CHART 6
TROUBLESHOOTING
CHART 4
YES
POSSIBLY MIXTURE TOO LEAN!
VALVE FOR BLOCKAGE.
ARE GAS LINES CLEAR?
SEE REPAIR PARTS DIAGRAM.
YES
POSSIBLY MIXTURE TOO RICH!
YES
CHECK MIXER AND BURNER FOR
CLEAN?
NO #1
NO #2
NO #3
CHART 6
NO
BE SURE TO USE CORRECT GAS/VENTURI VALVE SIZE.
NO
CLEAN BOILER FLUE PASSAGES PER MAINTENANCE
AND CLEANING INSTRUCTIONS
NO
CLEAN MIXER AND BURNER PER MAINTENANCE AND
NO
RUNS SMOOTHLY FOR ABOUT 6
SECONDS THEN SHUTS OFF.
INDICATES POOR FLAME SIGNAL.
CHECK IGNITER/SENSOR
POSITION. TIP SHOULD BE
SLANTED TOWARDS BURNER
YES
CHECK FLAME SIGNAL >0.6uA?
CONSULT BOILER MFGR. FOR
SPECIFIC INSTRUCTIONS.
REQUIRES SPECIAL TOOLS.
YES
REPLACE IBC
56
CLEAN/REPLACE GAS LINES .
CLEANING INSTRUCTIONS
REPLACE BURNER
RESTORE
NO
IGNITER/SENSOR
TO CORRECT POSITION.
DO NOT RELOCATE.
OXIDE COATING ON
IGNITER PREVENTING
NO
FLAME SIGNAL.
REPLACE
IGNITER/SENOR.