After a cuple of month the fan starts shutting off at times with a loud bang. It started this just recently. I have switched back to the old thermostat to troubleshoot this. After reverting back it has not did this. I wanted to test the old before calling a repairman. Has anyone else had this or solved it? Otherwise it has worked great. When it turns off it sounds like you hit the furnace hard. It has no problems starting and running. Thank you for your time.