Ok, so im new to the pellet stove world. We just bought a used stove, it starts up feeding pellets good and has a high flame putting out good heat.after a little while the heat will turn to warm n stay between worm n cool never goes back to hot air blowing out. Flame fluctuates high low, pellets dont come out as fast as whem it first startes. Ive tested the auger motors they work, all the rubber vacuum hoses look to be new the previous owner replaced gaskets around door n glass. Any suggestions would be greatly appreciated