The only Carrier heat pumps I remember that energize the reversing valve in the heating mode OLD units, and had no O terminal. The RV was energized by W1, were run by relay logic(lots of relays, both 24 and 240v), and had electromechanical defrost controls.
Originally Posted by beenthere
Except their commercial 3 phase units(older ones that had the fans with the cables). Threw me for a loop some years ago.
That one has bit me too.
If more government is the answer, then it's a really stupid question.