Dunkirk Q90-200 Series II - Manual (Page 46)

46
Troubleshooting Chart 6
RUNS FOR 25-50 SECONDS,
THEN TURNS OFF.
CHECK FIRING RATE OF UNIT.
IS UNIT FIRING AT THE CORRECT RATE?
NO
DOES THE UNIT USE LP GAS.
YES
NO
CHECK GAS ORFICICE SIZE.
IS GAS ORIFICE SIZE CORRECT.
CHECK REPAIR PARTS LIST
FOR CORRECT SIZE. IS GAS ORIFICE
CLEAR OF BLOCKAGE.
ADJUST RATE AS DESCRIBED IN THE
CHECK OUT PROCEDURE AND
ADJUSTMENT SECTION
OF THE MANUAL.
CHART 5
NO #2
YES
CHECK BURNER FOR ANY DETERIORATION
IN THE FLAME PORTS. ARE BURNER PORTS
IN GOOD CONDITION.
NO
REPLACE WITH CORRECT
AIR BAFFLE.
YES
CHECK FLAME SIGNAL > 0.6uA?
CONSULT BOILER MFGR. FOR
SPECIFIC INSTRUCTIONS. REQUIRES
SPECIFIC TOOLS.
NO
YES
REPLACE BURNER
REPLACE IBC
BOILER SHUTS OFF BEFORE END OF
CALL FOR HEAT. ARE HI LIMIT
AQUASTAT CONTACTS CLOSED?
NO
BOILER OFF ON HIGH LIMIT. IS
ACTUAL BOILER WATER TEMP.
GREATER THAN HI LIMIT SET POINT
MINUS 30°F CONTROL DIFFERENTIAL?
NO
NO
REPLACE
AQUASTAT
OK
YES
SEE TROUBLESHOOTING PATH
#2 ABOVE
CHART 5
NO #3
CHART 5
YES
SET THERMOSTAT BELOW ROOM
TEMPERATURE TO END CALL FOR
HEAT
DOES CIRCULATOR PUMP STOP?
NO
ARE THERMOSTAT CONTACTS OPEN? REPLACE THERMOSTAT
NO
YES
REPLACE IBC
YES
VALE LIGHT IS OFF
REMOVE WIRING HARNESS
CONNECTION CN9 FROM GAS
CONTROL DOES GAS CONTROL
CLOSE?
NO
REPLACE GAS CONTROL
NO
YES
YES
DOES DRAFT BLOWER
STOP AFTER 30
SECOND POST PURGE?
NO
REPLACE IBC
YES
YES
SYSTEM OK
YES
REPLACE GAS CONTROL.
15 - TROUBLESHOOTING