Utica Dunkirk E72 Error Code

What does Utica Dunkirk E72 mean?

E72 signals that the combustion test reading on Utica-Dunkirk DCC/DCB condensing boilers fell outside the acceptable range during the automatic calibration sequence. The boiler's control board measured CO2 or flame signal values it could not validate, so it aborted calibration and locked out. E72 often appears alongside E92 and indicates recalibration is required.

Symptoms

• Boiler displays E72 during or after the automatic calibration procedure
• Burner shuts down before calibration sequence completes
• Boiler may restart but fails calibration repeatedly
• E92 may appear in conjunction with E72

Common causes

• Incorrect or low gas supply pressure at the appliance
• Flue gas recirculation back into the air inlet
• Partially blocked flue duct or terminal
• Contaminated or deteriorated flame/ionization sensing electrode
• Wrong gas type setting in parameter P02

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Diagnostic steps

1. Verify gas supply pressure

   Measure the inlet gas pressure at the boiler's pressure test port while the unit is firing. Natural gas minimum is 3.5" w.c.; LPG minimum is 8.0" w.c.

2. Inspect and clean the ionization/sensing electrode

   Remove the electrode, check for carbon deposits or cracks, and clean with fine emery cloth. Verify the electrode gap matches the specification in the IOM.

3. Check for flue recirculation

   Inspect the flue terminal location relative to walls, adjacent openings, and prevailing wind directions. Recirculation is a leading cause of combustion instability triggering E72.

4. Run the automatic calibration function

   With all heating zones open and maximum flow established, press and hold the two navigation buttons for 6 seconds to initiate the automatic calibration sequence. Monitor the display through all three power levels.

5. Perform manual calibration if automatic calibration fails

   Immediately after automatic calibration completes, enter manual calibration mode and adjust CO2 percentage at minimum, ignition, and maximum power points per section 9.9 of the IOM.

When to call a professional

Call a licensed technician when combustion analysis equipment is needed to verify CO2 concentrations at each firing rate. Manual calibration requires measuring flue gas composition with a calibrated analyzer — a task that must be performed by a qualified technician to ensure safe and efficient combustion within the manufacturer's specified range and to comply with local codes.