I have a Lennox Winslow ps40 stove. I had the stove set to number 3 heating and when the house got too warm and I lowered the temp to 2 after about 20 minutes there was no flame and no pellets in the pot, but the stove was still running. If I leave it at 3 it keeps running with no problems. I had a similar problem last year and changed the proof of fire snap switch and that fixed the problem. Could the switch malfunctioned again?