From August 2000 until December 2004 the unit worked flawlessly. Jan/Feb 2005 the problems started. And while I'm typing it's happening again...I had to reset the unit.Originally posted by MikeJ
Sounds similar to a problem I ran into once. Took awhile for me to realize that when only one zone was calling, there was not enough air flow and the limit would trip (open), causing the burners to shut off and the blower to run until the unit cooled down. Then it would relight just after the blower quit and run for a bit and do the same thing. I opened both zones and didn't have this happen so I deduced that one zone only was too restrictive.
Try keeping both zones calling with a setting of 80 or so. Open your windows and see if the unit will continue to run. Or if you can, manually open both zones.
Another thing is set an appointment with a better company or the utility but let the house cool to a low temp., Then when the tech gets there let him up the temp and see what happens with only one zone calling. Just a thought.