Goodman Heat Pump 3T GSZ160361

We had the aforementioned heat pump installed in 2016. I scheduled a heat pump check up because our heating bill has significantly increased and we noticed our AUX heat had been running more. We understood that the weather has been in the 20’s and 30’s and this may be normal but it had been a year since our last check so we figured the timing was appropriate.

It happened to be 64 today when the tech arrived. The regular heat was on and the AUX had only been on around 10 mins in the early morning. He immediately went upstairs and told me he had a head pressure reading of 600psi which was causing the condenser to stop and tripping the AUX heat (which was not currently on during his reading) This was happening “to keep it from exploding due to the pressure”. He said it would be another $500 to run additional tests. About an hour later he told me I likely needed a new compressor. I responded “you’re kidding me, that was replaced less than 11 months ago”. He said he needed to do a few more tests to confirm. He then asked quite a few questions about my thermostat but changed nothing. Another hour went by and he came back in and said he was sorry, he couldn’t find anything wrong, he was sorry it wasn’t colder so he could diagnose it better and maybe our split system was causing it. Asked for the now grand total of 585.00 and let without giving me the first piece of paper about what he found or any of his readings.

Was it even possible for him to get a reading of 600psi head pressure with the heat pump still working? Can it just suddenly fall back to normal like it never happened? Or was I taken?