York Furnace Error Codes

8 error codes for York furnace models. Each links to the full diagnostic procedure from the service manual.

CodeDescription

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

MyPros+ Max

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Step-by-step tests with expected resistance, voltage, and continuity values
Wiring diagram references and connector pinouts
Verified part numbers when replacement is required

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M+ Max·York Furnace

1 Flash on my York Furnace

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Flame sensed without a call for heat

From Service Manual 801776, p.28:

1.Check for gas valve stuck open, gas valve slow closing, incorrect wiring (gas valve energized when it should not be), defective ground, or flame rod shorted to ground.

2.Measure control board supply voltage at the test points. Expected: 12 VDC and 5 VDC; a drop below 4.75 VDC on the logic rail points to a failed onboard regulator.

3.Inspect all connectors on the main control for corrosion, thermal stress, or backed-out pins. Reseat each connector with the power disconnected.

Part WPW10804018

Electronic control board

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