Error code reference

A.O. Smith Water Heater Error Code 551

Abnormal solenoid gas valves: driving circuit fault for the solenoid gas valves.

SourceA.O. Smith 710/710 ASME - Service Manual: Troubleshooting & Maintenancep. 16

A.O. Smith codes A.O. Smith water heater codes

Diagnostic procedure

The full 551 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

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First diagnostic step

If hot water is shut off but flames are still visible through the burner sight window, immediately shut off gas and power and contact Technical Service Department.

SourceA.O. Smith 710/710 ASME - Service Manual: Troubleshooting & Maintenancep. 16

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More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

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Where this code is documented

1 manual in the MyPros+ library documents this code for A.O. Smith water heater.

Models covered by the manuals that document this code

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The full 551 procedure

Where this code is documented

Models covered by the manuals that document this code

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