.my Rheem criterion II gas furnace runs good for 4-6 hours and holds temps per thermostat, then it won't start unless I open up front panel and flick one of two small fans. It kicks right on then and runs for another 4-6 hours. I've tried blowing these two small fans with air and also vacuuming them, this has brought mixed results, some times it runs well for a few days vs hours stopping and starting normally. Every time it stops or does not start on it's own flicking those one of those small fans it starts up just fine runs for those 4-6 hours as described earlier. Any help or diagnosis is appreciated.