Carrier Error Code 34: Ignition/Flame Sense Fault
Warning: Your Carrier furnace isn't igniting properly and has locked out. This usually requires professional diagnosis and repair.
How to Fix Carrier Code 34
- Step 1: Check your gas supply. Make sure other gas appliances are working.
- Step 2: Check the furnace filter. A dirty filter restricts airflow, which can affect combustion.
- Step 3: Reset the furnace by turning off the breaker for 30 seconds, then turning it back on. If the error returns, call a qualified HVAC technician.
How to Reset Carrier Code 34
- Turn off the furnace power switch, usually located on or near the unit.
- Turn off the circuit breaker for the furnace. Wait 30 seconds.
- Restore power at the breaker and flip the furnace switch back on.
- Set the thermostat to call for heat. If the error code returns after 2-3 ignition attempts, the fault requires repair.
What does 34 mean?
Error code 34 on a Carrier furnace indicates an ignition or flame sensing issue. The control board isn't detecting a stable flame after the ignition sequence. This can happen for a few reasons, but it usually means the furnace has shut down as a safety precaution. The furnace will likely attempt to restart a few times before locking out completely, displaying the error code.
Affected Models
- Performance Series Furnace
- Comfort Series Furnace
- Infinity Series Furnace
- Performance Series
- Base Series Furnace
- Performance Boost Furnace
- Performance Boost 95 Furnace
- WeatherMaker 8000
- WeatherMaker 9300
- Infinity 80
- WeatherMaker Furnace
- 24ABC6 Air Conditioner
- 25HBC5 Heat Pump
- Performance Series Heat Pump
- Infinity Series
- Base Series
- Comfort Series
- Infinity Series Heat Pump
- Comfort Series Heat Pump
- Infinity 20 Heat Pump with Greenspeed Intelligence
- Comfort 80 Gas Furnace
- WeatherMaker Furnace
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Flame Sensor | KP29HQ047 | — |
| Gas Valve | EF32CW176 | — |
| Ignition Control Module | — | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 11 | No Previous Error | Info |
| 12 | Blower On After Power Up | Warning |
| 13 | Limit/Rollout Fault | Critical |
| 14 | Ignition Lockout | Critical |
| 21 | Gas Heating Lockout | Critical |
| 22 | Abnormal Flame | Critical |
| 23 | Pressure Switch Fault | Warning |
| 24 | Secondary Voltage Fuse | Warning |
| 31 | High Stage Pressure Fault | Warning |
| 32 | Low Flame Sense | Warning |