I should have said that I intend to check the piston while the system is down. The service bulletins available describe it better. I am concerned about the possibility that the piston might be sticking. This is not the first time the system has done this. I could not confirm at what time of day or what the sequence was which started this. Its been almost 3 yrs since the last occasion. I am wondering if this could have been " morning syndrome". No codes where available when I arrived. Owner knew how to reset and clear history. It was a holiday and I'm not sure which compressor was lead at that time or how long it had been off.
The oil I have removed is not good. Testing indicates moisture but not at really high levels. Color was darker than I'm used to. Since I'm not sure how much was lost and have moisture and an odd color. My decision to change the oil is mostly because I am already pretty much there. Yes, I know flushing a barrel is costly and not 100% successful. At this point, I have not verified that a large quantity of oil is in the barrel. Could have been low to start with. I am only called when they cannot make things run! Nice to be needed. LOL