FieldBench
Carrier codes

Carrier

COMM OUT

Lockout

No communication with outdoor

Outdoor dropped off ABCD.

Walk COMM OUT in Diagnose

3 plates — walk the one on the cabinet

First check

1 Is Y actually at the contactor?

On Carrier 59MN7 a silent outdoor is often no Y. Measure 24 VAC coil-to-C at the contactor on a cool call. Outdoor on the same ABCD pair.

Expect: ~24 VAC at the coil when the indoor is calling.

If fail: Indoor Y / IFC / stat — not a capacitor.

The rest of the walkthrough is Diagnose.

On the plates

  • Outdoor on the same ABCD pair.
  • Outdoor events, not only indoor Last 10.
  • Setup outdoor model matches the plate.
  • Same ABCD pair at the outdoor.
  • Contactor-only outdoor will never talk.
  • Setup outdoor ID vs plate.

Plates that use COMM OUT

Same number, other makers

COMM OUT on Carrier is not the same code on these plates.