This is my first post here. I am looking for a little help. I have a 2 stage, 2 ton split system installed three years ago. Every season it has given me trouble. Thermistors, reversing valve, leaking coil in the York air handler. I decided to have a different local guy do the repairs this time when it broke (not the original installer). The unit was in lockout for low water temperature. Another bad thermistor. I also had them check the freon level because I felt it was not heating properly. When the system was working "properly" (in my opinion) it would blow 100 degrees from the register, but it was now only 90. The guy says the pressures are not reading correctly and that the low side was way too high. He did overcharge it, he told me that. The compressor was building pressure just fine. He determines that the TXV valve is bad. Couple days go by and he comes back while I am at work and replaces the TXV (trip number two). When I get home, the registers are blowing 80 degrees from second stage. I call back to say something isn't right. I only have a two degree difference between first stage and second stage and that used to be 10 degree difference. They come back out and tell me the compressor is bad. He says when he left on trip two that there was a 10 degree difference between first and second stage and that it was blowing 90 degrees in stage two when he left. He also told me that the TXV was installed backwards three years ago. He doesn't know whether the original installer did that or climate master. I don't think the installer installs the TXV inside the geo unit. Am I wrong about that? Anyway, point of my question is this. Is it possible that maybe this service guy has the TXV backwards and that is what caused the compressor to go bad within several hours? Could they have gotten dirt in it or something else to make the compressor die. It just seems odd to me that the compressor was fine for three years and was good the day they got here, but now after they work on it and it runs for several hours that the compressor is bad. Is it possible to see if the reversing valve is installed backward now without taking it apart? I could take pictures to show you.
Any help would be greatly appreciated.