Carrier Error Code 12: Blower On After Power Up
How to Fix Carrier Code 12
- Step 1: Turn off the HVAC system at the thermostat.
- Step 2: Wait a few minutes, then turn the system back on to see if the error clears. If it doesn't, proceed to the next step.
- Step 3: Contact a qualified HVAC technician to diagnose and repair the issue.
How to Reset Carrier Code 12
- 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 12 mean?
The Carrier error code 12, signaled by a specific LED blink pattern on the control board, indicates that the blower motor is running when it shouldn't be immediately after the unit powers up. This typically points to a problem within the system's control logic, preventing the blower motor from cycling on and off as expected. It's not a gas leak or immediate safety hazard, but it will likely prevent your system from heating or cooling your home effectively.
This issue often arises from a faulty relay on the control board that's stuck in the 'on' position, or a miscommunication between the thermostat and the unit's control board. In some cases, it could also be a sign of a failing blower motor that's not responding correctly to the control signals. Because it involves electrical components, troubleshooting should be left to a qualified HVAC technician.
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
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Blower Motor Relay | — | — |
| Control Board | — | — |
| Blower Motor | — | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| 11 | No Previous Error | Info |
| 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 |
| 33 | Limit/Rollout Switch Lockout | Critical |