I have a 2011 Big Country 3450TS. it has the above referenced fireplace. we've used the fireplace a lot and it has always worked well. lately , it stops throwing heat after awhile. if I turn it completely off, after five minutes or so I can turn it on and it will throw heat again. I don't think it worked like this in the past. I believe it would continue to throw heat as long as I had it turned on. I suspect either the over-temp cutout on the heater, or the thermostat control is faulty. anyone else had this problem with this unit? I have the unit out and am going to test it tonight.