Utica Dunkirk E63 Error Code
/E65 Combustion level out of range Check flue recirculation and combustion level
Source: dccf-115__utdu-dccf-115-dccf-205-dcbf-75-dcbf-165-iom.pdf
What does Utica Dunkirk E63 mean?
E63 is stored in the fault history when the combustion control detects the ionization signal is outside the acceptable range during burner operation — specifically in the context of the E63/E65 combined anomaly where the fan speed has reached a maximum correction limit. The combustion level is out of range and the control has exhausted its normal self-correction. This typically points to flue recirculation or a partially blocked flue duct.
Symptoms
- E63 (often listed as E63/E65) appears in the fault-history log.
- Fan may be running at elevated speeds as the combustion controller attempts to correct.
- Boiler may cycle on and off more frequently than normal during heating demand.
- E65 or E67 often appears alongside E63 confirming the combustion correction has reached its maximum.
Common causes
- Flue gas recirculation at the vent terminal re-entering the combustion air supply.
- Flue duct partially obstructed, reducing draft and skewing the air/fuel ratio.
- Sensing electrode fouled with combustion deposits, degrading the ionization signal.
- Gas supply pressure out of specification for the installed gas type.
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Diagnostic steps
Inspect the flue terminal for recirculation
Check the outdoor vent terminal location and condition. Confirm exhaust is not re-entering the combustion air intake. Reposition the terminal if recirculation is observed.
Check flue duct for obstruction
Inspect the full length of the flue run for blockages, bird nests, ice, or collapsed sections. Clear any obstruction found.
Clean or replace the sensing electrode
Remove and inspect the ionization/sensing electrode. Clean deposits carefully per the service manual — do not use abrasive materials. Replace the electrode if physically damaged.
Verify gas supply pressure
Measure static and operating gas pressure at the valve inlet port with a manometer. Confirm the reading is within the manufacturer's published specification.
Perform automatic calibration
After correcting physical issues, run the automatic calibration sequence from the installer menu to re-establish the combustion reference map.
When to call a professional
Call a licensed technician if E63 persists after clearing the flue and cleaning the sensing electrode. Combustion analysis with a flue-gas analyzer, gas valve inspection, and recalibration require factory-level training and specialized instruments. Operating the boiler with an unresolved out-of-range combustion level is a safety risk.
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Other Utica Dunkirk Error Codes
,E28,E40,E50,E160,E321,and E431 -Indicate possible faulty components. 53 - Indic
, 78 and 92 - Indicates possible wrong calibration, a new calibration is needed.
,E135 - Indicate the gas supply has been interrupted, ignition has failed or fla
,E 133, E 134,E 135, E 09,E 15,E 128 and E 384 - are displayed it is possible to
Gas Valve Connection Cable 日 10 External Probe Fault 12 Water Flow Switch Open 1
Water Refill Enabled E 19 Max Time Of Water Refill 20 Central Heating Flow NTC F
Flue NTC Fault E40 Central Heating Return NTC Fault Hot Water NTC Fault (tank ve
PCB to be set by the "Calibration Function" E 171 Fan parameter Out of range in
87 Communication error E92 Combustion test alarm during auto-setting E 1 109 Pre
E11 between the supply and return temperatures too Sensor not/poorly connected N
Temperature of heat exchanger is above the normal range (high- limit thermostat
5 burner start-up failures that the air inlet and exhaust flue are not blocked C
Sources: dunkirk.com