What error codes does a Utica or Dunkirk boiler display?

Modern Utica-Dunkirk condensing boilers — DCC-115/205, DCB-75/165, the flue-vented DCCF/DCBF variants, and the DMG-240 modulating boiler — use 2–3 digit E-prefix fault codes on the front-panel control display. The E0X–E1X range covers temperature-sensor faults (supply, return, heat-exchanger NTCs) and ignition / flame-loss conditions; E3X covers fan, supply/return swap, flame loss, and SCU-board communication; E4X covers water pressure, deaeration, and Delta-T faults; E5X covers calibration and PCB programming; E6X–E7X covers combustion correction limits and calibration-test alarms; the E1XX range (E109, E110, E125, E129, E130, E134) covers safety thermostat, flame-loss lockouts, and flue-NTC overtemperature on DCC/DCB platforms. The cast-iron SSE/UB/UCS/USVA gas-fired line and Megasteam oil-fired range have their own legacy fault flags documented per-model in the IOM. Press the Reset button for at least 2 seconds to clear soft faults; persistent faults need diagnosis using the per-code descriptions in the model-specific installation and operation manual.

What does E110 mean on a Dunkirk DCC or DCB boiler?

E110 indicates the safety thermostat has tripped due to overtemperature in the heat exchanger — the manual-reset overheat thermostat opened because water temperature at the primary heat exchanger exceeded a safe limit. The most common cause is a circulator pump that is blocked, seized, or not running; secondary causes are air trapped in the heating circuit reducing effective water flow, partially or fully closed system zone valves restricting flow, or a faulty thermostat / damaged thermostat cable giving a false trip. Do not attempt to reset immediately — allow the heat exchanger to cool completely (at least 15–20 minutes after shutdown) before inspecting. Verify the circulator runs and all zone/isolating valves are fully open, bleed radiators and system high points to clear air, then check the safety thermostat continuity (resistance >1.5 ohm after cooling indicates a failed thermostat). After corrections, hold reset for 2 seconds. Recurring E110 without a clear cause indicates a circulation design problem or heat exchanger scaling that needs professional diagnosis.

What does E130 mean on a Utica-Dunkirk condensing boiler and how is it different from E110?

E130 indicates the NTC flue-gas temperature sensor has detected an overtemperature condition — flue exhaust temperature has exceeded its maximum safe limit. E130 is a lockout fault requiring manual reset. The difference from E110: E110 trips on the heat exchanger safety thermostat (water-side overheat), while E130 trips on the flue-side NTC sensor (exhaust-side overheat). Both share the same root causes — a circulation failure that allows heat exchanger temperatures to climb — but E130 specifically signals the flue path is reaching unsafe temperatures. Causes include a blocked or seized circulator pump causing inadequate flow through the primary heat exchanger, air trapped in the primary circuit, a faulty NTC flue sensor triggering at below-threshold temperatures, or a damaged primary heat exchanger with partial internal blockage from scale or sludge. Allow the boiler to cool to ambient (at least 20 minutes), verify pump operation and that system pressure is between 15–30 psi, bleed any air from the circuit, and inspect the flue NTC wiring connector. Repeat overtemperature events risk permanent heat exchanger damage — a recurring E130 needs professional assessment of system water quality and possible heat exchanger descaling.

What does E38 mean on a Dunkirk DMG-240?

E38 indicates a communication error between the main boiler control and the SCU (system control unit) auxiliary PCB. The SCU is an optional add-on PCB that provides analog 0–10 V output, additional zone control, or HRU integration. The most common cause is removing the SCU PCB without running the auto-detect deregistration procedure — the main board still expects to see it. Other causes: loose wiring harness between the SCU and main board, SCU internal failure, or a damaged connector on the main board. Diagnose by opening the control enclosure and checking LED indicator D3 on the SCU PCB: continuous = OK, flashing = no connection (check wiring), no signal = no voltage or faulty PCB (check power, then replace). If the SCU PCB has been removed intentionally, navigate to the installer menu and run the auto-detect sequence to deregister it. SCU PCB replacement requires factory training because the auto-detect procedure and any associated parameter changes can interfere with zone control, analog outputs, and modulation behavior.

What does E44 mean on a Utica-Dunkirk DMG-240 and how do I clear it?

E44 indicates the temperature difference between the supply and return water is excessively high — greater than the maximum Delta-T configured in installer parameter P35. Heat is being added to the water faster than the heating system can extract it, typically caused by a flow restriction or circulation failure. The boiler shuts down to prevent heat exchanger damage. Common causes: circulator pump not delivering adequate flow (impeller blocked or pump set to wrong speed), closed or partially closed zone valves reducing flow through the heat exchanger, air lock in the heating circuit, or supply / return NTC temperature sensors swapped or incorrectly positioned producing an artificially high differential reading. Fix sequence: confirm the supply pipe is warmer than return and the pump is audibly running; inspect every zone and balancing valve in the active loop; verify the supply sensor is on the supply line and the return sensor is on the return line (not swapped); bleed air from all high points and restore system pressure to 15–20 psi; verify P35 is set per system design and has not been incorrectly modified. Persistent E44 faults can damage the stainless heat exchanger and need professional flow / scaling assessment.

What does E36 mean on a Utica-Dunkirk DMG-240 and is it the same as flame loss codes on DCC/DCB models?

E36 on the DMG-240 indicates flame loss — the burner ignited successfully but the flame was lost during normal operation. The ionization sensor stopped detecting current while the gas valve was open, causing the controller to shut down the gas valve and lock out for safety. On DCC/DCB models, the analogous condition is E129 (12 consecutive flame losses) for hard lockout and E70 for micro-interruption events; the underlying physics is the same. Common causes for both: insufficient gas supply pressure causing flame instability (must remain above 3.5" w.c. for natural gas under load), partially blocked flue duct causing combustion air starvation, flue gas recirculation contaminating combustion air, contaminated or worn ionization electrode with weak signal (must exceed 3 µA threshold), or a gas valve that opens partially or modulates erratically. Inspect the electrode for carbon deposits and correct gap, verify dynamic gas pressure at high input, walk the flue terminal and full duct run for restrictions, then perform automatic calibration after any combustion work. Combustion analysis with a calibrated CO/CO₂ meter is needed if E36 recurs.

What does E42 mean on a Dunkirk DMG-240 and what does the system pressure need to be?

E42 indicates the onboard low water pressure sensor has detected system pressure below the minimum required threshold (15 psi cold), or that the sensor wiring is disconnected. This code refers specifically to the factory-installed low-water pressure switch inside the boiler, not any field-installed external low-water cutoff. The boiler locks out to prevent dry-firing. Most common cause is a slow system leak the automatic fill cannot keep up with; secondary causes are a waterlogged expansion tank, loose pressure sensor wiring, or a failed onboard sensor. Fix: read the tridicator gauge, walk the entire piping run for drips at fittings / circulators / zone valves / relief valve discharge / expansion tank connections, repair any leak before refilling, then add water through the fill valve to reach 15–20 psi. Verify the pressure-sensor wiring connector is firmly seated on the sensor terminals and the sensor is fully threaded into the boiler block (a loose sensor causes intermittent / false E42). If pressure cannot be restored to 15 psi or leaks are found in internal piping or the heat exchanger, call a licensed technician.

What does E55 mean on a Utica-Dunkirk DCC or DCB boiler?

E55 means the PCB control board is not programmed or has not been calibrated — most often after a PCB replacement when the new board has not yet had the automatic calibration function run, or when calibration data on the board has been corrupted. The boiler will not fire until calibration is completed. Procedure: confirm the replacement PCB part number matches the boiler model (an incorrect board cannot be calibrated); open all heating zones and have at least one thermostat calling for heat to provide maximum flow; press and hold both navigation buttons simultaneously for 6 seconds until the display shows 'On' — the automatic calibration sequence runs through three power levels (maximum, ignition, minimum) and takes 3–5 minutes; immediately after, enter manual calibration mode and verify CO₂ at minimum, ignition, and maximum power using a combustion analyzer per IOM section 9.9. Manual calibration is mandatory and requires combustion analysis equipment — improper calibration leads to inefficient combustion, elevated CO production, and potential safety hazards. Contact Utica-Dunkirk technical service at 1-800-325-5479 if calibration cannot complete.

What's the difference between E72 and E55 on a Utica-Dunkirk boiler?

Both E72 and E55 are calibration-related but signal different stages: E55 means calibration has never been completed (the PCB is unprogrammed or calibration data has been lost), while E72 means calibration was attempted but failed — the combustion test reading fell outside the acceptable range during the automatic sequence. E72 often appears alongside E92 (combustion test alarm) and indicates recalibration is required after correcting the underlying cause: incorrect or low gas supply pressure (NG minimum 3.5" w.c., LPG 8.0" w.c. measured at the inlet test port while firing), flue gas recirculation back into the air inlet (inspect the flue terminal location relative to walls, adjacent openings, prevailing wind), partially blocked flue duct or terminal, contaminated or deteriorated flame / ionization sensing electrode (clean with fine emery cloth, verify gap), or wrong gas-type setting in parameter P02. After correcting the cause, run automatic calibration first; if it still fails, perform manual calibration with a combustion analyzer per IOM section 9.9. Manual calibration must be performed by a qualified technician.

When should I call a service technician for a Utica-Dunkirk boiler fault?

Several Utica-Dunkirk codes always require a licensed technician: E55 / E72 / E92 calibration faults (mandatory combustion-analyzer verification at three firing rates), E17 / E38 PCB / SCU board failures (replacement requires the full automatic + manual commissioning calibration sequence), E83 OpenTherm communication faults that persist after wiring inspection (PCB OpenTherm interface is likely damaged), E110 / E130 overheat lockouts that recur after pump and air-purge inspection (indicates heat exchanger scaling or system flow design problem), E129 hard lockout after 12 consecutive flame failures (combustion testing and possibly gas valve replacement), and any fault that returns immediately after replacing a component. Utica-Dunkirk technical service is reachable at 1-800-325-5479. PCB replacement specifically must be followed by a full commissioning calibration sequence per the IOM, and combustion adjustment work must comply with local codes — all reasons not to attempt these repairs without factory-trained service support.

Quick Answer

Utica Boilers and Dunkirk are sister US boiler brands under ECR International, sharing gas and oil platforms — DCC/DCB and DCCF/DCBF condensing, DMG-240 modulating, SSE/UB/UCS/USVA cast-iron, UB90 condensing, and Megasteam oil. Modern controls show 2–3 digit E-prefix fault codes covering ignition, sensor, pressure, blower, and combustion-calibration faults — most common are E110, E130, E36, E42, E55, and E72.

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By Octavian Ghindea

Co-founder & CTO · Reviewed May 2026

What error codes does Utica Dunkirk display?

E03

Supply temperature sensor open circuit — reseat connector or replace NTC

E08

Return temperature too low — check return NTC, circulation, supply/return reversal

E12

Heat exchanger high-limit overheat — verify circulation, P35 setpoint

E36

Flame loss during operation — gas pressure, electrode, flue draw

E38

SCU PCB communication error — check D3 LED, run auto-detect after removal

E42

Onboard low water pressure switch open — refill, check for leaks

E44

Supply/return Delta-T too high — pump flow, zone valves, sensor swap, P35

E55

PCB unprogrammed/uncalibrated — run automatic + manual calibration

E65

Fan reached max speed correcting flame signal — flue recirculation or fouled electrode

E72

Combustion test alarm during auto-calibration — gas pressure, recirculation, electrode, P02

Common questions about Utica Dunkirk equipment

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