This year my Quadrafire CB 1200 Freestanding has been randomly shutting down. It seems to be at times after it shuts down from burning and then it reaches set temp to turn back on and will drop pellets and shut down without lighting them. That's what I'm thinking as I find unburned pellets in the burnpot after we notice it's shutdown. It's random times and could go fine for a couple days without any trouble or it could be after a couple rounds coming on and off where I set my temp on the wireless thermostat. I've cleaned everything good, new batteries in thermostat and receiver, new thermocouple wire and cover. What can I try or what do you think could be causing the problems? Thanks for any help you can give as it hasn't even started the really cold season and it's doing this.