Bryant, Payne, Carrier Furnace Error Codes
Look up error codes to identify furnace problems and estimate repair costs.
Locating the furnace error code
Refer to the furnace glossary if you need help identifying furnace parts or terms.
All high-efficiency furnaces and most mid-efficiency furnaces show error codes on the control board, either as a flashing LED sequence or on a display .
Where to find the control board and inspection port
The furnace control board is almost always in the lower compartment. You can view the error code LED or display through a small, clear plastic inspection port in the centre of the lower furnace cover.
If the control board isn’t in the lower compartment, it’s in the upper compartment.
How to access the inspection port
Furnaces with upper and lower furnace covers — The inspection port is usually on the lower furnace cover and is accessible without removing the cover.
Furnaces with a one-piece front cover — Remove the front cover first. The inspection port is usually on the secondary cover for the lower compartment.
If the control board is in the upper compartment — You need to remove the upper furnace cover. If there are thumb screws, loosen them and pull the cover out from the screw location. If there are no screws, slide the cover straight up, then pull it out.
Error codes
Don’t turn off the power to the furnace while troubleshooting — unless instructed otherwise. Turning off the power clears the current error code.
Observe the flashing LED sequence or display code, which may repeat in a loop. Watch it carefully, make note of the sequence or digits, and match it up with the corresponding code below:
1 short and 1, 2, or 3 long flashes
Continue to the Secondary diagnostic →
1 short and 4 long flashes
Furnace locked out from heating attempts
Possible plugged filter or faulty flame sensor, high limit switch, or gas valve. Professional diagnosis required.
2 short and 3 long flashes
Pressure switch not opening
Blocked intake/exhaust or faulty pressure switch or inducer motor.
3 short and 1 long flashes
Pressure switch did not close or reopened
Blocked intake/exhaust or faulty pressure switch or inducer motor.
3 short and 2 long flashes
Continue to the Secondary diagnostic →
3 short and 3 long flashes
Limit circuit fault — high limit or rollout limit switch open
Blocked filter or secondary heat exchanger, or failed blower motor. Professional diagnosis required.
4 short and 1 long flashes
Blower outside valid speed range
Faulty blower motor. Professional diagnosis required.
4 short and 2 long flashes
Inducer outside valid speed range
Faulty inducer motor or control board. Professional diagnosis required.
4 short and 3 long flashes
Pressure switch calibration faulty
Blocked intake, exhaust, condensate trap, or faulty pressure switch.
4 short and 5 long flashes
Continue to the Secondary diagnostic →
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Furnace repairs should only be performed by a certified technician.
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