I bought a new summer heat pellet stove and installed it myself. The first time I used it worked great for about an hour. Then it said loss vacuum shutting down. I let it shut all the way down and started it again. It worked until the fan came on and it said loss vacuum shutting down again. The next morning I started it again and it worked great for about an hour and a half and said loss vacuum shutting down. Any one have any ideas what is going on with this stove? technical support is not much help.