Utica Dunkirk E69

What does Utica Dunkirk E69 mean?

E69 is stored in the fault history when the combustion control detects the combustion level is outside its acceptable operating range. The ionization signal from the sensing electrode does not match the expected value for the current firing rate. This typically follows sustained anti-wind events (E62, E67) or indicates flue recirculation that has degraded combustion air quality.

Symptoms

• E69 appears in the fault-history log, frequently paired with E62, E67, or E53.
• Burner may cycle off during a heating call as the controller fails to maintain a stable combustion signal.
• Reduced heat output or extended recovery times.
• Possible lockout on E53 if the combustion deviation triggers the obstruction/calibration fault.

Common causes

• Flue gas recirculation contaminating the combustion air supply at the terminal.
• Flue duct obstruction reducing draft and distorting the combustion ratio.
• Sensing electrode fouled with combustion deposits, reducing the ionization signal.
• Gas pressure out of specification, causing a lean or rich combustion mixture.

Diagnostic steps

1. 01

   Check flue recirculation and terminal position

   Inspect the outdoor vent terminal for signs of exhaust re-entering the air inlet. Reposition or extend the flue duct as needed.

2. 02

   Inspect and clean the sensing electrode

   Remove the sensing electrode and inspect for carbon deposits or corrosion. Clean per the service manual instructions — do not use abrasive materials.

3. 03

   Verify gas supply pressure

   Measure inlet gas pressure with a manometer while the boiler is firing. Confirm the reading is within the published specification for the installed gas type.

4. 04

   Check flue duct for obstruction

   Inspect the full flue run for blockages, bird nests, condensate traps, or collapsed sections that would reduce draft.

5. 05

   Perform the automatic calibration function

   After correcting any vent or electrode issues, run the boiler's automatic combustion calibration sequence per the IOM instructions to reset the combustion reference baseline.

When to call a professional

Call a licensed technician if E69 recurs after cleaning the electrode and correcting the vent system. Combustion analysis with a calibrated flue-gas analyzer is required to confirm safe operation. Gas valve adjustment, calibration parameter reset, and flue reconfiguration must be performed by a factory-trained technician.