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Error code reference

Carrier Furnace Error Codes

14 error codes documented with diagnostic procedures.

Have your model number? Get codes specific to your unit.
11No previous code stored; stored status codes are erased when power (115VAC or 24VAC) to…12Blower runs for 90 seconds after power up if unit is powered up during a call for heat…13Limit circuit lockout occurs if the limit, draft safeguard, flame rollout, or blocked…14Ignition lockout; system failed to ignite gas and prove flame in 4 attempts; control will…21Gas heating lockout; control will NOT auto-reset.22Abnormal flame-proving signal; flame is proved while gas valve is de-energized23Pressure switch did not open.24Secondary voltage (24VAC) fuse is open.31Pressure switch did not close or reopened; if open longer than 5 minutes, inducer shuts…32Low-heat pressure, draft safeguard (when used), or auxiliary limit switch (downflow only)…33Limit circuit fault; indicates a limit, draft safeguard, flame rollout, or blocked vent…34Ignition proving failure; if flame is not sensed during the trial for ignition period…43Low-heat pressure, draft safeguard (when used), or auxiliary limit switch (when used)…45Control circuitry lockout; auto-reset after one hour due to gas valve relay stuck open…

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More Carrier error codes

Common questions

How do I find the error code on my Carrier Furnace?
Most Carrier furnaces show the code directly on the control panel display. If your model has no display, it can be read by entering diagnostic mode with the key sequence for your model. The full procedures include model-specific instructions for reading codes.
Are these codes specific to my model?
The codes here apply broadly to Carrier furnaces. Meanings and diagnostic steps can vary by model and production year, so enter your model number for model-specific information and procedures.
What do I do if my code is not listed?
Some codes are model-specific or only appear in diagnostic mode. Enter your model number to get codes specific to your unit, or contact us. We update the database continuously from manufacturer service documentation.
How much does it cost to access the full diagnostic procedures?
A 3-day pass is $9.95 one-time and gives full access to all brands, codes, and procedures. Monthly access is $29/month with unlimited access to everything including Max AI diagnostics.