Utica Dunkirk E20 Error Code
,E28,E40,E50,E160,E321,and E431 -Indicate possible faulty components. 53 - Indic
Source: dcc-115__utdu-dcc-115-dcc-205-dcb-75-dcb-165-iom.pdf
What does Utica Dunkirk E20 mean?
E20 indicates a fault with the Central Heating (CH) flow NTC temperature sensor on Utica-Dunkirk DCC/DCB condensing boilers. The control board cannot read a valid signal from the sensor, so the boiler locks out to prevent uncontrolled heating. The sensor measures supply-side water temperature and is critical to modulation and safety control.
Symptoms
- Boiler display shows E20 and burner shuts down
- No central heating output despite heat demand
- Boiler enters lockout and will not restart automatically
- Control panel fault indicator illuminates
Common causes
- Faulty or failed CH flow NTC temperature sensor
- Loose or corroded wiring connector at the sensor or PCB
- Broken or shorted sensor lead wire
- PCB input circuit failure
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Diagnostic steps
Check wiring and connectors
Inspect the wiring harness between the CH flow NTC sensor and the PCB. Look for loose pins, corrosion, or damaged insulation and reseat any loose connectors.
Measure sensor resistance
Disconnect the sensor and use a multimeter to measure resistance. Cross-reference the reading against the NTC resistance-temperature chart in the IOM; an open circuit or significantly out-of-range value confirms sensor failure.
Replace the CH flow NTC sensor
Install a replacement OEM NTC sensor, verify it is seated correctly in the sensor pocket, and reconnect the wiring harness securely.
Reset the boiler
Press and hold the RESET button for at least 2 seconds. If E20 clears, confirm normal operation through a full heating cycle.
Contact technical service if fault persists
If E20 returns after sensor replacement, the PCB input channel may be defective. Contact Utica-Dunkirk technical service at 1-800-325-5479.
When to call a professional
Call a licensed HVAC technician if the fault persists after inspecting wiring and replacing the sensor, or if you are not equipped to perform electrical continuity and resistance measurements safely. PCB replacement requires a qualified technician to configure and calibrate the control board per the manufacturer's commissioning procedure to avoid introducing additional faults.
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Other Utica Dunkirk Error Codes
, 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
False flame signal Ignition transformer defective Gas valve defective valve and
Sources: dunkirk.com, uticaboilers.com