Utica Dunkirk E37 Error Code
Communication error with SU PCB Bad connection Check whether the SU PCB has been
Source: dmg-240__utdu-dmg-240-iom.pdf
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.
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Diagnostic steps
Disconnect power to the boiler
Turn off the boiler at the service switch and verify power is off before opening the control enclosure.
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.
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.
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.
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.
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Other Utica Dunkirk Error Codes
,E28,E40,E50,E160,E321,and E431 -Indicate possible faulty components. 53 - Indic
, 78 and 92 - Indicates possible wrong calibration, a new calibration is needed.
,E135 - Indicate the gas supply has been interrupted, ignition has failed or fla
,E 133, E 134,E 135, E 09,E 15,E 128 and E 384 - are displayed it is possible to
Gas Valve Connection Cable 日 10 External Probe Fault 12 Water Flow Switch Open 1
Water Refill Enabled E 19 Max Time Of Water Refill 20 Central Heating Flow NTC F
Flue NTC Fault E40 Central Heating Return NTC Fault Hot Water NTC Fault (tank ve
PCB to be set by the "Calibration Function" E 171 Fan parameter Out of range in
87 Communication error E92 Combustion test alarm during auto-setting E 1 109 Pre
E11 between the supply and return temperatures too Sensor not/poorly connected N
Temperature of heat exchanger is above the normal range (high- limit thermostat
5 burner start-up failures that the air inlet and exhaust flue are not blocked C
Sources: dunkirk.com