Cointra
Cointra Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E01
Furnace does not ignite, burner never lights, display shows E01 shortly after a call for heat.
Ignition Failure / No Flame Detection
E02
Furnace attempts to start but shuts down with E02, fan may run briefly, no stable flame.
Flame Loss During Operation
E03
Furnace locks out with E03, combustion fan may start but unit shuts down quickly, no ignition.
Air Pressure Switch / Flue Fan Fault
E04
Furnace displays E04 and will not start; may occur immediately after power-on.
Overheat / High Limit Thermostat Trip
E05
Display shows E05, furnace stops heating, may occur intermittently during operation.
Flow Temperature Sensor Fault (NTC)
E06
Furnace shows E06, heating stops, fan may continue to run for a short time.
Return / Room Temperature Sensor Fault
E07
Furnace displays E07 and will not start, or stops shortly after starting.
Return Temperature Too High / Overheat on Return
E08
Furnace shows E08, burner shuts down, fan may continue to run.
Flow Temperature Too High / Primary Overheat
E09
Furnace displays E09, no heating, may occur after a power surge or wiring work.
Gas Valve Circuit Fault
E10
Furnace shows E10, unit does not start, may be accompanied by no fan operation.
Low Supply Voltage / Power Supply Fault
E11
Furnace displays E11, burner does not light, fan may run.
Ignition Electrode / Spark Failure
E12
Furnace shows E12 and locks out, often after several failed ignition attempts.
Multiple Ignition Failure Lockout
E13
Furnace displays E13, unit may start but then shuts down, sometimes with unusual noises from the flue.
Flue Gas Temperature Too High
E14
Furnace shows E14, no heating, may occur after thermostat or control wiring changes.
Communication Error with Room Thermostat / Control
E15
Furnace displays E15, unit may continue to run at reduced performance.
Outdoor Temperature Sensor Fault (if equipped)
E16
Furnace shows E16, heating stops, sometimes after long operation.
Condensate Drain Fault (for condensing models)
E17
Furnace displays E17, unit may not respond to thermostat commands.
Internal Control Board Fault
E18
Furnace shows E18, fan may run continuously, no heating.
Safety Chain Open (Limit or Safety Device Open)
E19
Furnace displays E19, intermittent operation, sometimes accompanied by clicking relays.
Fan Speed / Tachometer Fault
E20
Furnace shows E20, no heating, may occur after configuration changes.
Configuration / Parameter Error
Symptom
Furnace continues to blow cool air after the burner has shut off and does not stop.
Fan Stuck On / Post-purge Overrun
Symptom
Furnace cycles on and off frequently (short cycling), with very short run times.
Short Cycling
Symptom
Furnace does not start at all; no display, no fan, completely dead.
No Power / Dead Furnace
Symptom
Furnace emits a burning dust smell when starting after a long period of inactivity.
Dust Burn-off on Heat Exchanger
Symptom
Furnace emits a metallic or scraping noise when the fan starts or stops.
Fan Wheel Rubbing / Misalignment
Symptom
Furnace emits a persistent gas smell around the unit or in the room.
Gas Leak in Furnace or Gas Line
Symptom
Furnace makes loud banging or booming noises at startup (delayed ignition).
Delayed Ignition / Burner Light-off Problem
Symptom
Furnace operates but carbon monoxide detector in the home alarms during or shortly after operation.
CO Emissions / Flue Gas Spillage
Symptom
Furnace produces a high-pitched whine or loud humming noise during operation.
Fan or Inducer Motor Noise
Symptom
Furnace runs but produces insufficient heat; rooms do not reach set temperature even though the unit cycles normally.
Underfiring / Low Heat Output
Symptom
Furnace runs but some rooms are much colder than others; airflow seems weak at distant vents.
Poor Air Distribution / Duct Imbalance
Symptom
Furnace starts but shuts down after a few minutes, with warm air initially then cool air.
Overheat and Lockout Without Displayed Code
Symptom
Furnace vibrates excessively and causes rattling noises in ducts and nearby structures.
Excessive Vibration / Imbalanced Fan
Symptom
Room thermostat calls for heat but the furnace does not respond; display shows standby, no error code.
No Heat Call Recognition
Symptom
Soot or dark staining appears around the flue terminal or furnace casing.
Incomplete Combustion / Sooting
Symptom
Water or moisture is found under or around the furnace cabinet.
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Furnace does not ignite, burner never lights, display shows E01 shortly after a call for heat.
|
Ignition Failure / No Flame Detection | View Details |
| E02 |
Furnace attempts to start but shuts down with E02, fan may run briefly, no stable flame.
|
Flame Loss During Operation | View Details |
| E03 |
Furnace locks out with E03, combustion fan may start but unit shuts down quickly, no ignition.
|
Air Pressure Switch / Flue Fan Fault | View Details |
| E04 |
Furnace displays E04 and will not start; may occur immediately after power-on.
|
Overheat / High Limit Thermostat Trip | View Details |
| E05 |
Display shows E05, furnace stops heating, may occur intermittently during operation.
|
Flow Temperature Sensor Fault (NTC) | View Details |
| E06 |
Furnace shows E06, heating stops, fan may continue to run for a short time.
|
Return / Room Temperature Sensor Fault | View Details |
| E07 |
Furnace displays E07 and will not start, or stops shortly after starting.
|
Return Temperature Too High / Overheat on Return | View Details |
| E08 |
Furnace shows E08, burner shuts down, fan may continue to run.
|
Flow Temperature Too High / Primary Overheat | View Details |
| E09 |
Furnace displays E09, no heating, may occur after a power surge or wiring work.
|
Gas Valve Circuit Fault | View Details |
| E10 |
Furnace shows E10, unit does not start, may be accompanied by no fan operation.
|
Low Supply Voltage / Power Supply Fault | View Details |
| E11 |
Furnace displays E11, burner does not light, fan may run.
|
Ignition Electrode / Spark Failure | View Details |
| E12 |
Furnace shows E12 and locks out, often after several failed ignition attempts.
|
Multiple Ignition Failure Lockout | View Details |
| E13 |
Furnace displays E13, unit may start but then shuts down, sometimes with unusual noises from the flue.
|
Flue Gas Temperature Too High | View Details |
| E14 |
Furnace shows E14, no heating, may occur after thermostat or control wiring changes.
|
Communication Error with Room Thermostat / Control | View Details |
| E15 |
Furnace displays E15, unit may continue to run at reduced performance.
|
Outdoor Temperature Sensor Fault (if equipped) | View Details |
| E16 |
Furnace shows E16, heating stops, sometimes after long operation.
|
Condensate Drain Fault (for condensing models) | View Details |
| E17 |
Furnace displays E17, unit may not respond to thermostat commands.
|
Internal Control Board Fault | View Details |
| E18 |
Furnace shows E18, fan may run continuously, no heating.
|
Safety Chain Open (Limit or Safety Device Open) | View Details |
| E19 |
Furnace displays E19, intermittent operation, sometimes accompanied by clicking relays.
|
Fan Speed / Tachometer Fault | View Details |
| E20 |
Furnace shows E20, no heating, may occur after configuration changes.
|
Configuration / Parameter Error | View Details |
| – |
Furnace continues to blow cool air after the burner has shut off and does not stop.
|
Fan Stuck On / Post-purge Overrun | View Details |
| – |
Furnace cycles on and off frequently (short cycling), with very short run times.
|
Short Cycling | View Details |
| – |
Furnace does not start at all; no display, no fan, completely dead.
|
No Power / Dead Furnace | View Details |
| – |
Furnace emits a burning dust smell when starting after a long period of inactivity.
|
Dust Burn-off on Heat Exchanger | View Details |
| – |
Furnace emits a metallic or scraping noise when the fan starts or stops.
|
Fan Wheel Rubbing / Misalignment | View Details |
| – |
Furnace emits a persistent gas smell around the unit or in the room.
|
Gas Leak in Furnace or Gas Line | View Details |
| – |
Furnace makes loud banging or booming noises at startup (delayed ignition).
|
Delayed Ignition / Burner Light-off Problem | View Details |
| – |
Furnace operates but carbon monoxide detector in the home alarms during or shortly after operation.
|
CO Emissions / Flue Gas Spillage | View Details |
| – |
Furnace produces a high-pitched whine or loud humming noise during operation.
|
Fan or Inducer Motor Noise | View Details |
| – |
Furnace runs but produces insufficient heat; rooms do not reach set temperature even though the unit cycles normally.
|
Underfiring / Low Heat Output | View Details |
| – |
Furnace runs but some rooms are much colder than others; airflow seems weak at distant vents.
|
Poor Air Distribution / Duct Imbalance | View Details |
| – |
Furnace starts but shuts down after a few minutes, with warm air initially then cool air.
|
Overheat and Lockout Without Displayed Code | View Details |
| – |
Furnace vibrates excessively and causes rattling noises in ducts and nearby structures.
|
Excessive Vibration / Imbalanced Fan | View Details |
| – |
Room thermostat calls for heat but the furnace does not respond; display shows standby, no error code.
|
No Heat Call Recognition | View Details |
| – |
Soot or dark staining appears around the flue terminal or furnace casing.
|
Incomplete Combustion / Sooting | View Details |
| – |
Water or moisture is found under or around the furnace cabinet.
|
Condensate Leak | View Details |
No matching codes found
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