Hvac Service Manuals & Error Codes

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

528Manuals

147Error Codes

18Brands

MyPros+ Max

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Step-by-step tests with expected resistance, voltage, and continuity values
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M+ Max·Whirlpool HVAC

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 Hvac Repair

CodeBrandDescription

1LGPCB sees IDU pipe or air thermistor as open or shorted (varies by...10LGLS902HPV/LS122HPV/LA09xHV/LA12xHV: PCB sees ODU discharge pipe...12LGPCB sees IDU middle pipe thermistor as open or shorted.13LGReactor or electronic noise filter failure in ODU.14LGCompressor Phase Amperage Error.2LGPCB sees ODU or IDU thermistor(s) as open or shorted (varies by unit...21LGInverter compressor high amperage.22LGInverter unit high amperage.23LGInverter DC link voltage too low.24LGHigh or low pressure switch open (low opens at 14 PSI, high at 600...25LGLow voltage or high voltage feeding unit.26LGInverter compressor seized, not rotating or not proving rotation.27LGInverter compressor amperage over 100A for a split second.28LGInverter DC link voltage too low.29LGInverter compressor high amperage.

Show all 18 brands

Amana American Standard Aprilaire Bryant Carrier Frigidaire GE Honeywell Kenmore Lennox LG Maytag Rheem Samsung Thermador Trane Whirlpool York

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Access 528 service manuals, 147 error codes, and step-by-step diagnostics for hvac repair.