[Richard]

There is a very easy way to test to see if the HWH makes the compressor come on. Put the HWH into air mode. Press any of the up buttons. If the compressor comes on, then it’s something to be aware of.

I don’t know if this is related to your issue or not. But what I have observed to happen if the HWH is left in auto mode is the compressor will come on and run until something breaks trying to level the coach. In my case it was an air bag. On my coach there was a overpressure relief valve that was supposed to let off at 125, but it did not. Perhaps mine had been adjusted by a PO in the past.

Given that any of our coaches may have had modifications different from the factory, you will just have to make both a pneumatic and electrical diagram of YOUR setup to help noodle out the problem.

This is what I hear you saying, but I am using different words than you do. I install a new compressor, it works for a period of time, then it blows the head gasket, then it runs forever trying to build pressure.

Hmmm, what if it runs forever happens first, therefore causing the head gasket to fail. Chicken or egg deal.