Utica Dunkirk E34

What does Utica Dunkirk E34 mean?

E34 on the Utica-Dunkirk DMG-240 condensing boiler indicates a fan fault. The control board commanded the combustion fan to run but did not receive the expected speed feedback signal, or the fan failed to reach the required RPM within the allowed time. Without confirmed fan operation, the pre-purge sequence cannot complete and the boiler locks out before any ignition attempt.

Symptoms

• Boiler display shows E34 and burner does not ignite
• Fan may be silent or audibly running slower than normal
• Boiler enters lockout before spark is heard
• Fault recurs immediately after each reset attempt if fan is failed

Common causes

• Fan motor seized or bearing failed
• Loose or disconnected wiring between fan and PCB
• Obstructed fan wheel (debris, insect nest in flue)
• Inadequate flue draw reducing fan efficiency below the required speed setpoint
• Failed PCB fan speed feedback circuit

Diagnostic steps

1. 01

   Check fan wiring and connector

   Inspect the fan wiring harness and the connector at the PCB. A loose plug or broken wire can prevent the speed signal from reaching the control board even if the fan is running.

2. 02

   Verify the fan runs on power-up

   Listen for the pre-purge fan run at boiler startup. If silent, the motor is failed or disconnected. If running but slow, suspect mechanical restriction or worn bearings.

3. 03

   Inspect the flue for obstruction

   Check the flue terminal and all flue ductwork for blockages that increase backpressure and prevent the fan from reaching the required speed. Clear any debris found.

4. 04

   Check flue draw adequacy

   Verify that the flue installation meets length and bend specifications in the DMG-240 IOM. Excessive flue length or too many bends creates backpressure that triggers E34.

5. 05

   Replace the fan if motor has failed

   If the fan motor is seized or electrically open, replace it with the OEM fan assembly for the DMG-240 model. Verify wiring polarity and speed sensor connection before powering up.

When to call a professional

Call a licensed technician if the fan requires replacement or if the flue system requires modification to reduce back pressure. Fan replacement involves working inside the boiler cabinet with electrical components, and any changes to the flue system must comply with local codes and the manufacturer's approved venting configurations to maintain safe combustion.