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Error code reference

York Furnace Error Codes

8 error codes documented with diagnostic procedures.

Have your model number? Get codes specific to your unit.
1 FlashFlame sensed without a call for heat.2 FlashLow fire pressure switch (1LP) contacts are stuck in the closed position; control must…3 FlashFlame rectification could not be established (applies to both 1st stage and 2nd stage)…4 FlashOpen limit circuit (includes Primary Limit, Auxiliary Limit, and Rollout Switches).6 Flash1LP has opened five times during one call for heat.7 FlashFlame rectification could not be established; flame rectification must be maintained for…8 FlashFlame rectification has been lost 5 times during 1 call for heat after it was recognized…LED on constantlyThe control discovered an internal fault during its self-check procedure; all operations…

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Step-by-step tests, expected values, wiring diagram references, and verified part numbers.

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Common questions

How do I find the error code on my York Furnace?
Most York 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 York 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.