Error code reference

Carrier HVAC Error Code 46

Brownout condition: secondary voltage of the transformer has fallen below 15Vac for a period exceeding four seconds.

SourceCarrier Fan Coil Units - Service Manual: FB/FE/FF/FH/FV/FX/FZ/PF Seriesp. 16

Diagnostic procedure

The full 46 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

Check transformer input and output voltages. Condition clears automatically when secondary voltage rises above 17Vac for more than four seconds.

SourceCarrier Fan Coil Units - Service Manual: FB/FE/FF/FH/FV/FX/FZ/PF Seriesp. 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 Carrier hvac.

Models covered by the manuals that document this code

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The full 46 procedure

Where this code is documented

Models covered by the manuals that document this code

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