Utica error codes — full list with meanings | TroubleAtlas

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HVAC Error Codes · Manufacturer index

Utica error codes

The complete list of Utica fault codes shown on the display, each with what it means and the page that explains how it is diagnosed and fixed.

50documented codes
50with documented causes
Utica boiler with the fault code shown on the display
Quick Answer

Utica heating appliances display 50 documented error codes. Each code below opens its own page with the official meaning, the documented causes, the safety assessment and the parts involved.

01

All Utica Error Codes

50 codes, each with its own page. Click a code to open the meaning, the documented causes and the repair.

CodeWhat it means
14Pressure switch does not close during prepurge 1
36More than 3 conduit pre-safety switch errors in 24 hours have occurred
Air Switch Not ClosedAir pressure switch not closing during pre-purge 1
Air Switch Not OpenAir pressure switch not opening during pre-purge 0
Corrupted Error Num- berRAM byte was corrupted to an unknown error code
Corrupted Error NumberRAM byte was corrupted to an unknown error code
Ex. Low Flow ProtectionFlow is too low, demand needs to be stopped with fan at ignition speed*, but no error needed to be stored at…
Fan Not RunningFan is not running for more than 60 seconds
Fan Too FastFan runs too fast for more than 60 seconds
Fan Too SlowFan runs too slow for more than 60 seconds
Fill WarningError generated directly when pressure drops below Minimal_Pressure
Filling Too MuchToo many automated filling at- tempts in a short time period
Flame Before IgnitionFlame is detected before ignition
Flue Pressure ErrorFlue pressure switch is closed
Flue Temperature Too HighFlue temperature is higher than set maximum
Gas Pressure ErrorGas pressure switch open for more than E2_GPS_Timeout
GasValve Relay ErrorFailure detected in the gas valve relay
High Temp ErrorT_Supply sensor measures over Stay_Burning_Temp for a period of Max_Value_Period
Ignition ErrorFive unsuccessful ignition at- tempts in a row
Ion Check FailedInternal software error
Low Water Pressure SensorLow water pressure, occurs when the pressure drops below Mini- mal_Pressure, or when the pres- sure drops…
Max. Flue Lock ErrorFlue temperature exceeded the maximum flue temperature
Max. Thermostat Lock ErrorThe external overheat protection is enabled or the T_Supply sen- sor measures a temp
Refhi Too Lo ErrorInternal hardware error
Refhi2 Too Lo ErrorInternal hardware error
Reflo Too Lo ErrorInternal hardware error
Reflo2 Too Lo ErrorInternal hardware error
Register ErrorInternal software error
Reset Button ErrorToo many resets in a short time period
Safety Relay ErrorFailure detected in safety relay
Stack ErrorInternal software error
State ErrorInternal software error
T DHW OpenDHW sensor open
T DHW ShortedDHW sensor shorted
T Flue OpenFlue sensor open
T Flue ShortedFlue sensor shorted
T Outdoor OpenOutdoor sensor open
T Outdoor ShortedOutdoor sensor shorted
T Return OpenReturn sensor open
T Return ShortedReturn sensor shorted
T Supply OpenSupply sensor open
T Supply ShortedSupply sensor shorted
Too Many Flame Fai- luresThree time flame lost during 1 demand
Too Many Flame FailuresThree times flame lost during 1 demand
WD Config ErrorWatchdog fan configuration set- ting error
WD Error RegisterInternal software error
WD Error RomInternal software error
Wrong EEPROM Sig- natureContents of E2prom is not up to date
Wrong EEPROM SignatureContents of E2prom is not up to date
verrouillageExternal overheating protection is activated or the T_Supply sensor measures a temperature
02

What Fails Most Often on Utica

Grouped from the official meaning of each of the 50 codes above — not from opinion. The number is how many different fault codes point at that component.

ComponentCodesExamples
Fan5Ex. Low Flow Protection, Fan Not Running, Fan Too Fast, Fan Too Slow
Flue5Flue Pressure Error, Flue Temperature Too High, Max. Flue Lock Error, T Flue Open
Temperature Sensor5High Temp Error, T Outdoor Open, T Outdoor Shorted, T Supply Open
Pressure Switch414, Air Switch Not Closed, Air Switch Not Open, Gas Pressure Error
Ignition4Flame Before Ignition, Ignition Error, Too Many Flame Fai- lures, Too Many Flame Failures
Overheat2Max. Thermostat Lock Error, verrouillage
Dhw Sensor2T DHW Open, T DHW Shorted
Return Sensor2T Return Open, T Return Shorted
03

Parts & Prices

The parts most often involved in the Utica faults listed above.

Fan / blower assembly
OEM Part · Utica
Check price View price
Flue / air intake seal kit
OEM Part · Utica
Check price View price
Temperature sensor (NTC)
OEM Part · Utica
Check price View price
Air pressure switch
OEM Part · Utica
Check price View price
Compatible Fan / blower assembly
Compatible · Generic
Check price View price
Compatible Flue / air intake seal kit
Compatible · Generic
Check price View price
Compatible Temperature sensor (NTC)
Compatible · Generic
Check price View price
Compatible Air pressure switch
Compatible · Generic
Check price View price
Reconditioned Fan / blower assembly
Used / Tested · Utica
Check price View price
Reconditioned Flue / air intake seal kit
Used / Tested · Utica
Check price View price
Reconditioned Temperature sensor (NTC)
Used / Tested · Utica
Check price View price
Reconditioned Air pressure switch
Used / Tested · Utica
Check price View price

Prices and availability vary by region and are shown by the retailer, not by TroubleAtlas.

04

Diagnostic Tools

What an engineer uses to work through the codes on this page.

Digital Multimeter (TRUE RMS)

For testing electrode resistance and PCB voltages

$35–$80 View price

Gas Leak Detector

Essential for checking connections after any gas valve work

$25–$45 View price

Manometer / Pressure Gauge

To measure gas inlet and burner pressure

$40–$90 View price

Combustion Analyzer

For verifying flue gas readings after repair

$180–$350 View price
Full HVAC diagnostic toolkit
05

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Written by TroubleAtlas Technical Team · Last updated: 2026-08-02 · Sources: manufacturer service documentation · How we verify
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