Error code reference

Aprilaire Furnace Error Code 1 Flash

System lockout - flame was not sensed during ignition attempts and the control has locked out after multiple retries.

SourceAprilaire Hvac - Service Manual - RA661001: 1870p. 33-34

Diagnostic procedure

The full 1 Flash 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.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Reset the control by turning the thermostat off and then back on.

SourceAprilaire Hvac - Service Manual - RA661001: 1870p. 33-34

Unlock with pass

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 Aprilaire furnace.

Models covered by the manuals that document this code

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The full 1 Flash procedure

Where this code is documented

Models covered by the manuals that document this code

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