FieldBench
Carrier codes

Carrier

RV

Lockout

No shift

Reversing valve did not stroke.

Walk RV in Diagnose

Sign in for the next measurement

First check

1 Confirm O/B is energized the way THIS outdoor expects

Most US splits energize O in cool. Some Rheem/Ruud energize B in heat. Read the Carrier 50FC diagram, not a generic heat-pump card. O/B 24 VAC at the board on a heat call (or cool, depending on this controller’s logic — confirm silk).

Expect: Correct 24 V at the solenoid for the mode that is failing.

The rest of the walkthrough is Diagnose.

On the plates

  • O/B 24 VAC at the board on a heat call (or cool, depending on this controller’s logic — confirm silk).
  • Coil ohms. Then the piston — a stuck RV is not a charge call.

Plates that use RV