Ideal
Ideal Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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F1
Ideal furnace locks out shortly after start, burner does not light, fan may run briefly then stop
Ignition Lockout / Ignition Failure
F10
Ideal furnace shows F10, no ignition, or immediate lockout after call for heat
Ignition Lockout – Repeated Failed Starts
F11
Furnace displays F11, blower may run continuously, no heating output
Low-Voltage / Communication Fault
F12
Ideal furnace shows F12, unit may start but shuts down at random, sometimes with display flicker
Power Supply / Voltage Fault
F13
Furnace displays F13, runs briefly then shuts down, may be associated with condensate issues on condensing Ideal models
Condensate Drain / Trap Fault
F14
Ideal furnace shows F14, no ignition, or immediate shutdown after flame is established
Flame Signal Weak / Unstable Combustion
F15
Furnace displays F15, blower may run but burner does not light, or unit cycles without heating
Low Temperature Rise / Inadequate Heating
F16
Ideal furnace shows F16, unit may overheat or shut down unexpectedly, sometimes with noisy operation
Fan Speed / Blower Control Fault
F17
Furnace displays F17, no response to thermostat, or intermittent operation with communication-related error
External Control / Smart Interface Fault
F18
Ideal furnace shows F18, unit may lock out after several failed attempts, often in very cold weather
Frozen or Blocked Flue / Intake
F19
Furnace displays F19, frequent cycling, may not maintain set temperature
Short Cycling / Overheat-Reset Pattern
F2
Ideal furnace attempts to start but shuts down quickly, fan may run, no sustained flame
Flame Detection Failure
F20
Ideal furnace shows F20, no ignition, or immediate lockout with gas-related warning
Incorrect Gas Type / Configuration Fault
F3
Furnace will not start, inducer fan may not run, F3 displayed on Ideal control
Pressure Switch Open / Airflow Proving Failure
F4
Ideal furnace locks out with F4, burner shuts down during operation, may cycle on and off frequently
High Limit / Overheat Trip
F5
Furnace fails to start or shuts down with F5, fan may run continuously, no heat
Rollout Switch Trip / Flame Rollout Detected
F6
Ideal furnace shows F6, inducer runs but ignition sequence does not proceed, or unit cycles without lighting
Airflow / Fan Proving Fault (Inducer or Combustion Air)
F7
Furnace displays F7, will not start, thermostat appears to call for heat but no response
Thermostat / Control Signal Fault
F8
Ideal furnace shows F8, blower runs but no heat, or intermittent heating with control board error
Control Board / Internal Electronics Fault
F9
Furnace displays F9, runs briefly then shuts down, may be accompanied by unusual flame behavior
Gas Valve / Gas Supply Fault
Symptom
Blower fan runs continuously even when thermostat is not calling for heat
Stuck Fan Relay / Fan Control Fault
Symptom
Burner flame appears yellow, lazy, or produces soot; possible smell of exhaust
Poor Combustion / Incomplete Burning
Symptom
Furnace causes carbon monoxide alarm to activate when running
Combustion Gas Spillage / Heat Exchanger or Flue Fault
Symptom
Furnace causes strong vibration or rumbling felt through the house when running
Excessive Vibration / Imbalanced Blower
Symptom
Furnace does not start at all; no fan, no clicking, no display or indicator lights
No Power / Dead Furnace
Symptom
Furnace emits a burning smell when first started or after long inactivity
Dust Burn-Off / Overheating Components
Symptom
Furnace frequently turns on and off in short bursts, house temperature fluctuates
Short Cycling (Thermostat or Sizing Issue)
Symptom
Furnace is very noisy during operation; rattling, banging, or high-pitched squealing from the unit
Mechanical Noise / Vibration Fault
Symptom
Furnace runs but energy bills are unusually high and house still feels cool
Low Efficiency / Poor Heat Transfer
Symptom
Furnace runs but produces no heat; blower operates, but supply air is cold
Burner Not Firing / No Flame
Symptom
Furnace runs but some rooms remain cold or airflow is weak at certain registers
Insufficient Airflow / Distribution Issue
Symptom
Furnace runs for a few minutes then shuts off; blower continues to run with no heat
Overheating / High Limit Cycling
Symptom
Furnace starts normally but shuts down when blower starts; may trip breaker
Blower Motor Overload / Electrical Fault
Symptom
Furnace starts then shuts off after a few seconds; repeated short attempts to ignite
Short Cycling on Ignition / Flame Loss
Symptom
Furnace will not respond to thermostat; thermostat appears to work but furnace stays off
Thermostat Control / Low-Voltage Circuit Fault
Symptom
Strong smell of gas near the furnace, especially during or after operation
Gas Leak / Unsafe Gas Escape
Symptom
Visible rust or staining around the burner compartment; possible water inside combustion area
Internal Condensate / Heat Exchanger Leak
Symptom
Water leaking from the base of the Ideal furnace or from internal panels
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| F1 |
Ideal furnace locks out shortly after start, burner does not light, fan may run briefly then stop
|
Ignition Lockout / Ignition Failure | View Details |
| F10 |
Ideal furnace shows F10, no ignition, or immediate lockout after call for heat
|
Ignition Lockout – Repeated Failed Starts | View Details |
| F11 |
Furnace displays F11, blower may run continuously, no heating output
|
Low-Voltage / Communication Fault | View Details |
| F12 |
Ideal furnace shows F12, unit may start but shuts down at random, sometimes with display flicker
|
Power Supply / Voltage Fault | View Details |
| F13 |
Furnace displays F13, runs briefly then shuts down, may be associated with condensate issues on condensing Ideal models
|
Condensate Drain / Trap Fault | View Details |
| F14 |
Ideal furnace shows F14, no ignition, or immediate shutdown after flame is established
|
Flame Signal Weak / Unstable Combustion | View Details |
| F15 |
Furnace displays F15, blower may run but burner does not light, or unit cycles without heating
|
Low Temperature Rise / Inadequate Heating | View Details |
| F16 |
Ideal furnace shows F16, unit may overheat or shut down unexpectedly, sometimes with noisy operation
|
Fan Speed / Blower Control Fault | View Details |
| F17 |
Furnace displays F17, no response to thermostat, or intermittent operation with communication-related error
|
External Control / Smart Interface Fault | View Details |
| F18 |
Ideal furnace shows F18, unit may lock out after several failed attempts, often in very cold weather
|
Frozen or Blocked Flue / Intake | View Details |
| F19 |
Furnace displays F19, frequent cycling, may not maintain set temperature
|
Short Cycling / Overheat-Reset Pattern | View Details |
| F2 |
Ideal furnace attempts to start but shuts down quickly, fan may run, no sustained flame
|
Flame Detection Failure | View Details |
| F20 |
Ideal furnace shows F20, no ignition, or immediate lockout with gas-related warning
|
Incorrect Gas Type / Configuration Fault | View Details |
| F3 |
Furnace will not start, inducer fan may not run, F3 displayed on Ideal control
|
Pressure Switch Open / Airflow Proving Failure | View Details |
| F4 |
Ideal furnace locks out with F4, burner shuts down during operation, may cycle on and off frequently
|
High Limit / Overheat Trip | View Details |
| F5 |
Furnace fails to start or shuts down with F5, fan may run continuously, no heat
|
Rollout Switch Trip / Flame Rollout Detected | View Details |
| F6 |
Ideal furnace shows F6, inducer runs but ignition sequence does not proceed, or unit cycles without lighting
|
Airflow / Fan Proving Fault (Inducer or Combustion Air) | View Details |
| F7 |
Furnace displays F7, will not start, thermostat appears to call for heat but no response
|
Thermostat / Control Signal Fault | View Details |
| F8 |
Ideal furnace shows F8, blower runs but no heat, or intermittent heating with control board error
|
Control Board / Internal Electronics Fault | View Details |
| F9 |
Furnace displays F9, runs briefly then shuts down, may be accompanied by unusual flame behavior
|
Gas Valve / Gas Supply Fault | View Details |
| – |
Blower fan runs continuously even when thermostat is not calling for heat
|
Stuck Fan Relay / Fan Control Fault | View Details |
| – |
Burner flame appears yellow, lazy, or produces soot; possible smell of exhaust
|
Poor Combustion / Incomplete Burning | View Details |
| – |
Furnace causes carbon monoxide alarm to activate when running
|
Combustion Gas Spillage / Heat Exchanger or Flue Fault | View Details |
| – |
Furnace causes strong vibration or rumbling felt through the house when running
|
Excessive Vibration / Imbalanced Blower | View Details |
| – |
Furnace does not start at all; no fan, no clicking, no display or indicator lights
|
No Power / Dead Furnace | View Details |
| – |
Furnace emits a burning smell when first started or after long inactivity
|
Dust Burn-Off / Overheating Components | View Details |
| – |
Furnace frequently turns on and off in short bursts, house temperature fluctuates
|
Short Cycling (Thermostat or Sizing Issue) | View Details |
| – |
Furnace is very noisy during operation; rattling, banging, or high-pitched squealing from the unit
|
Mechanical Noise / Vibration Fault | View Details |
| – |
Furnace runs but energy bills are unusually high and house still feels cool
|
Low Efficiency / Poor Heat Transfer | View Details |
| – |
Furnace runs but produces no heat; blower operates, but supply air is cold
|
Burner Not Firing / No Flame | View Details |
| – |
Furnace runs but some rooms remain cold or airflow is weak at certain registers
|
Insufficient Airflow / Distribution Issue | View Details |
| – |
Furnace runs for a few minutes then shuts off; blower continues to run with no heat
|
Overheating / High Limit Cycling | View Details |
| – |
Furnace starts normally but shuts down when blower starts; may trip breaker
|
Blower Motor Overload / Electrical Fault | View Details |
| – |
Furnace starts then shuts off after a few seconds; repeated short attempts to ignite
|
Short Cycling on Ignition / Flame Loss | View Details |
| – |
Furnace will not respond to thermostat; thermostat appears to work but furnace stays off
|
Thermostat Control / Low-Voltage Circuit Fault | View Details |
| – |
Strong smell of gas near the furnace, especially during or after operation
|
Gas Leak / Unsafe Gas Escape | View Details |
| – |
Visible rust or staining around the burner compartment; possible water inside combustion area
|
Internal Condensate / Heat Exchanger Leak | View Details |
| – |
Water leaking from the base of the Ideal furnace or from internal panels
|
Condensate Leak | View Details |
No matching codes found
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