Gas and Oil Home Heating Furnaces - Furnace Burner Cycling

I have a Comfortmaker Furnace where the burner was cycling several times during the "On Cycle" once the thermostat kicked in to request heat. The burner would go on for about 2 minutes, then shut-off for about 30 seconds and then come on and go off again several times during the heating cycle. The filter was clean and none of the returns was blocked. I then suspected that for some reason the plenum was overheating and the limit switch was opening up the circuit for the gas valve/igniter. When I took out the Limit Switch to inspect it, I noticed that it had been touching one of the heat exchanger sections. I bent the sheet metal out a little where the limit switch was mounted and that fixed the problem. I would like to know if anyone else had a similar problem with Comfortmaker Furnaces. It appears that the hole for mounting the limit switch could have been better positioned so as to not risk it from directly contacting the heat exchanger and falsely opening the switch contact.

slc_ideas:

I agree.

seen it on carrier gas packs