My heat pump is not keeping my house cool even in mild (22' C) weather and my warranty tech cannot find the problem and is ready to give up. Please read over the sequence of events and what I've observed and give me the benefit of your experience and ideas!
I have a goodman GSZ130241AB heat pump split between outside and the attic. It's a two-tonne unit and the area it cools is about 1700 sq ft. The house is 2 years old, the HVAC stuff the same. The first summer I was here the unit worked well. It developed a leak and stopped working at some point, but this was repaired and the unit kept the house cool again.
This spring, I noticed it would not cool at all. Because of unrelated complications (home warranty), someone did not come out until some time in June. That visit was productive and they found that there was oil leaking out of the outside heatpump onto its pad, and that one of the components there needed to be replaced (had a small hole in it underneath). I think it was "the dryer" but I could be wrong about that. They also did the compressor as a precautionary measure.
After this, the unit did not work properly (kind of intermittent), and the outside insulated copper pipe would frost up. The service person checked everything up and down and could not figure out the problem. This went on for for some time. He checked for blockages, restrictions, blew out the coil (s), etcetera etcetera. Then a month later he gets back to me and tells me the compressor that was put in was actually for another refrigerant type, and not the proper match for the rest of my R-410A? system. This is apparently bad to mix the two types of refrigerant as they become corrosive. So, the problem was found.
Next thing that happened was they replaced the whole outside unit because of no parts availability (took a couple weeks again), and blew out the rest of the system with some kind of special AC cleaning stuff.
Now its the end of the summer, and the unit does not keep the house cool when its even mildly hot - but it does mostly function. Today for example the house reached 23' C when set for 21.5' C steady. After I noticed that it had reached 23 it took about an hour or so for it to come back down to 21.5 where the set point was. It's only about 20 - 22.5' C outside, so you can understand that this behaviour ends up being unpredictable, and when the service person comes here he checks the pressures and temps coming out of the duct work and says everything is fine.
I know how this unit should behave though, and when functioning properly the temp never wavers even on a 30' day.
Basically its at the point where I know the service guy doesn't want to hear from me and they are asking me questions like 'did you kepe the door open for a minute'. But I need this fixed and I need it fixed before the hot weather completely disappears. I'm crossing my fingers for a day next week that might get to 25' and maybe the problem will show up more obviously and stick around.
The way I see it, sure everything was checked, but that was before this unit was replaced, and something could have changed, or something else could have been done improperly. Putting in the wrong compressor is a pretty big oops in the first place IMO.
I want to try and work with this service person to get this solved so "call somebody else" doesn't really help me. Can anyone see whats being overlooked here? I'm pulling my hair out over this.
EDIT: The outside insulated copper pipe does not frost, the air coming out of my ducts is ~ 54' F on my cheap crappy probe thermometer, and I looked for ice on upper and lower coil and didn't see any.
Thanks for reading