Utica Dunkirk E37

What does Utica Dunkirk E37 mean?

E37 on the Dunkirk DMG-240 indicates a communication error between the main boiler control board and the SU (sequence unit) PCB. The main board cannot establish or maintain communication with the SU PCB over its internal bus. The boiler shuts down and displays E37 until the connection is restored or the PCB is replaced.

Symptoms

• E37 displayed on the DMG-240 control panel — boiler will not fire.
• No heating or hot water output.
• Control board is powered and display is active, but the burner does not attempt to start.
• Code persists through power cycling until the SU PCB seating issue is corrected.

Common causes

• SU PCB not fully seated in its connector on the PCU board — most common cause.
• Wiring harness between the SU PCB and the main board loose or damaged.
• SU PCB failed internally due to age, surge, or moisture ingress.
• PCU board connector socket damaged, preventing reliable PCB contact.

Diagnostic steps

1. 01

   Disconnect power to the boiler

   Turn off the boiler at the service switch and verify power is off before opening the control enclosure.

2. 02

   Re-seat the SU PCB

   Locate the SU PCB in the control section. Carefully press it firmly into the connector on the PCU PCB until it is fully and evenly seated. Reconnect power and observe whether E37 clears.

3. 03

   Inspect the wiring harness

   Check all wiring connectors between the SU PCB and the main control board for loose, corroded, or damaged contacts. Reseat each connector securely.

4. 04

   Run the auto-detect function

   If the SU PCB was removed and replaced, run the auto-detect function from the installer menu so the boiler control can recognize and configure the PCB.

5. 05

   Replace the SU PCB if fault persists

   If E37 remains after re-seating and wiring inspection, replace the SU PCB with the correct part number for the DMG-240 and re-run the auto-detect sequence.

When to call a professional

Call a licensed technician to replace the SU PCB or PCU board. Internal control board work on the DMG-240 requires manufacturer training to correctly run the auto-detect and parameter configuration sequences. Installing an incorrect or incompatible PCB can cause additional faults and damage the control system.