I had a Mr. Slim split system heat pump installed in my house. It was working very well until in my never-ending quest to save power, I decided to start turning it off at the breaker during the night and then back on again in the morning. My house is very tight and well insulated so the temperature would only drop from 72 to about 60 while having it off all night.
Normal start-up procedure was to wait until the sun was hitting the outside unit, then I would turn the breaker on (leaving all indoor units off) and wait 30 minutes before turning indoor units on. The house would then warm up to 72 in about 3 hours.
One morning after a colder than usual night (got down into the single digits F) - the house had gotten down to about 55 - someone else in the house turned the outside unit on earlier in the morning than usual. The heat pump hasn't worked well since. The lines going to the indoor units don't get as hot during heat mode, and they don't get as cold during defrost as they used to. The heat pump has a hard time holding 72 degrees in the house even running 24 hours/day.
My guess is that the compressor (or more specifically, the reed valves inside the compressor) have been damaged from starting it up cold.
Are there any professionals in here that would concur or am I totally off track here?
Thanks in advance for any input.
Keywords for future google search: heat pump compressor cold start damage breaker