Utica Dunkirk E38 Error Code
Communication error with SCU PCB Bad connection Defective SCU PCB Check the wiri
Source: dmg-240__utdu-dmg-240-iom.pdf
What does Utica Dunkirk E38 mean?
E38 on the Dunkirk DMG-240 indicates a communication error between the main boiler control and the SCU (system control unit) PCB. This optional auxiliary PCB provides functions such as analog 0–10 V output and additional zone control. If the SCU PCB is removed without running the auto-detect procedure, or if wiring to it fails, the main board logs E38 and shuts down.
Symptoms
- E38 displayed on the DMG-240 control panel — boiler will not operate.
- Code appears immediately after SCU PCB removal without running auto-detect.
- LED status indicator D3 on the SCU PCB flashes (no connection) or shows no signal (no voltage or faulty PCB).
- No heating or hot water output while E38 is active.
Common causes
- SCU PCB removed from the boiler without running the auto-detect function to deregister it.
- Wiring harness between the SCU PCB and main board is loose or disconnected.
- SCU PCB has failed internally — LED D3 shows no signal.
- Connector on the main board damaged, preventing reliable SCU communication.
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Diagnostic steps
Determine if SCU PCB is installed
Open the control enclosure and verify whether the SCU PCB is physically present. If it has been removed recently, the auto-detect procedure must be run to prevent E38.
Run the auto-detect function
If the SCU PCB was removed intentionally, navigate to the installer menu and run the auto-detect sequence. This deregisters the SCU PCB from the main board and should clear E38.
Check SCU PCB wiring
If the SCU PCB is installed, check all wiring connections from the SCU to the main board. Reseat loose connectors and inspect for damaged wires or corroded pins.
Check LED indicator D3 on the SCU PCB
A continuous LED signal means the PCB is working normally. A flashing signal means no connection — check wiring. No signal means no voltage or a faulty PCB — check power supply, then replace the PCB.
Replace the SCU PCB if necessary
If wiring is intact and D3 shows no signal, replace the SCU PCB with the correct replacement part. Re-run auto-detect after installation.
When to call a professional
Call a licensed technician to replace or configure the SCU PCB. The auto-detect procedure and any associated parameter changes require installer-level access and factory training. An incorrectly configured SCU PCB can interfere with zone control, analog outputs, and the boiler's modulation behavior.
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Other Utica Dunkirk Error Codes
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, 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
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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
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5 burner start-up failures that the air inlet and exhaust flue are not blocked C
Sources: dunkirk.com