Utica Dunkirk E55

What does Utica Dunkirk E55 mean?

E55 on Utica-Dunkirk DCC/DCB condensing boilers means the PCB control board is not programmed or has not been calibrated. This fault appears after a PCB replacement when the new board has not yet had the automatic calibration function run, or when calibration data stored on the board has been corrupted or lost. The boiler will not fire until calibration is completed.

Symptoms

• Boiler display shows E55 after a PCB replacement
• Boiler will not ignite or attempt to fire
• E55 may appear during or after a failed calibration attempt
• All other electrical functions appear normal

Common causes

• PCB replaced without running the commissioning calibration function
• Calibration data erased from PCB memory (power surge or PCB defect)
• Automatic calibration sequence interrupted before completion
• Incorrect PCB installed for the specific boiler model

Diagnostic steps

1. 01

   Confirm the correct PCB is installed

   Verify the replacement PCB part number matches the boiler model. An incorrect board will display E55 and cannot be calibrated.

2. 02

   Open all heating zones

   Before running calibration, ensure all zone valves are open and at least one thermostat is calling for heat to provide maximum flow and prevent overheating shutdown during the sequence.

3. 03

   Run the automatic calibration function

   Press and hold both navigation buttons simultaneously for 6 seconds until the display shows 'On.' The calibration sequence runs through three power levels (maximum, ignition, and minimum) and takes approximately 3–5 minutes.

4. 04

   Perform manual calibration

   Immediately after automatic calibration, enter manual calibration mode and verify CO2 at minimum, ignition, and maximum power using a combustion analyzer. Adjust as needed per section 9.9 of the IOM.

5. 05

   Verify E55 clears and boiler fires normally

   Once calibration completes successfully, E55 should clear. Run a full heating cycle and verify stable burner operation with no recurring faults.

When to call a professional

PCB calibration requires a combustion analyzer to verify CO2 concentrations at all three firing rates during manual calibration. This is a mandatory step that a technician must complete — improper calibration leads to inefficient combustion, elevated CO production, and potential safety hazards. Contact Utica-Dunkirk technical service at 1-800-325-5479 for assistance.