I have a Coleman Powermate 6-1/2 horsepower air compressor. I have always left it turned on all the time so that I would have air available whenever needed. A few times now, including twice in the last week now, I have came into the shop and found the compressor running continuous. When I have found it running, it appears that the relief valve has opened and it is blowing out of that. So today I decided that the pressure switch must not have shut it off and the pressure got too high and blew the relief valve, but the relief valve stayed open so the compressor never shut off. But I also wonder if the relief valve popped open prematurely and stayed open leaving the compressor running. So now I am wondering which do I replace, the relief valve or the pressure switch? What do you guys think?