Hi. Carrier 8000 2 speed, 580 uXT 100-16 80% AFUE Natural Gas, Installed in 1996 normally runs like a champ. Last week this happened and I just reset and it was good to go.

Last night husb left cold air intake grill covered and this morning I noticed I heard the fan cranking but no forced air heat coming from vents.

Noticed sensor reading either 1 then 3 or 3 then 1. When I reset it glares consistent. When I tell thermostat to fire up the sensor then begins the blinking. Have tried throwing all manual switches available. Any help welcome... of course it is a Sunday and of course I have a bad cold and of course we're having our first real winter storm.

Thanks everyone!
Bonnie B.

Figured it out. We have lift off!

Although I had waited 3 hrs before I reset last time (because after 3 times apparently you're out and directions say to wait 3 hrs), this time (about the
6th time) I shut the electricity off to the unit, waited 10 seconds, then turned it back on, set the thermostat and it fired right up. I had done all of the above before, it just must have a 'code' of its own that I finally happened to hit it right.