FieldBench
Carrier codes

Carrier

Unexpected

Hazard

Flame out of sequence

Flame with no trial.

Walk Unexpected in Diagnose

2 plates — walk the one on the cabinet

First check

1 Shut the gas cock first

On Carrier 48FC the rod sees flame with the valve de-energized. Shut the cock. If flame stays, the valve is leaking — replace it. Do not jump or energize it as a test. Shut the cock. Leaking valve or a welded relay.

Expect: Flame dies when the cock is shut.

If fail: Leaking valve. Replace. Do not leave the unit.

The rest of the walkthrough is Diagnose.

On the plates

  • Shut the cock. Leaking valve or a welded relay.
  • Do not keep cycling heat.

Plates that use Unexpected

Same number, other makers

Unexpected on Carrier is not the same code on these plates.