DIYbanter - View Single Post - Heat pump defrost control board and thermostat reversing valve voltage level

wrote:
(Sent here from alt.hvac)

This is Arizona and therefore only about 50F with low humidity.

Also in AZ.

About 15 years ago I owned a Knoell starter home in Chandler
with a Goettl heat pump on the roof. After the heat pump was
about 5 or 6 years old, the first time I would try to fire it up in
heat mode every year, it would be stuck in AC mode. On that
unit, there was a relay in the unit on the roof, controlled by the
thermostat, that applied line voltage to the reversing coil.
Popping off the cover and whacking the relay with the handle
of a screwdriver was enough to break it loose and it would
work for the rest of the heating season.

After about 3 years of that nonsense, got tired of the annual
trip to the roof and replaced the relay. No problems after that.

Don't know if this has anything to do with your problem, but
thought it was worth a mention.

Jerry