Furnace Service Manuals & Error Codes

Service manuals, error codes, and parts diagrams for furnace repair across all major brands.

211Manuals

400Error Codes

8Brands

MyPros+ Max

Get step-by-step furnace diagnostics from the service manual.

Step-by-step tests with expected resistance, voltage, and continuity values
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M+

M+ Max·Whirlpool Furnace

My appliance shows an error code

M+

Control board fault diagnosis

From Tech Sheet W10810403, p.8:

1.Access the service diagnostic mode using the tech sheet procedure. Record all stored fault codes from the error history, not just the most recent active code.

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 board for corrosion, thermal stress, or backed-out pins. Reseat each connector with the power disconnected.

Part WPW10804018

Electronic control board

Top Error Codes for Furnace Repair

CodeBrandDescription

1 FlashAmanaSystem lockout - excessive number of ignition retries or recycles;...2 FlashesAmanaPressure switch stuck closed - pressure switch circuit is closed even...3 FlashesAmanaPressure switch stuck open - pressure switch circuit does not close...4 FlashesAmanaOpen limit control or thermal protection device - primary limit,...5 FlashesAmanaOpen rollout control - rollout limit is open due to flame rollout...6 FlashesAmanaReversed polarity - 115V or 24V AC power leads are reversed...7 FlashesAmanaLow flame sense signal - micro-amp signal from the flame sensor is...8 FlashesAmanaPressure switch opened five times during a single call for heat...9 FlashesAmanaPrimary or auxiliary limit opened five times during a single call for...Continuous FlashingAmanaFlame sensed with no call for heat - flame detected when gas valve is...Continuous LightAmanaInternal control failure - the integrated ignition control has an...1LennoxReverse line voltage polarity.1TraneFlame sensed when no flame should be present.1 FlashLennoxFlame present with gas valve de-energized (control 103085).1 FlashYorkFlame sensed without a call for heat.

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