I have a Concord 80 plus furnace. The code I'm getting is Limit or rollout switch open. The burner goes out after a few minutes and the blower motor keeps running. If I wait it resets itself after 15 minutes it will do it 3 times then it won't reset for an hour. I found two limits on each side of the burner if I push the button the burner will come on. My question is are the limits bad or is something else causing it? I would appreciate any help.

The limits could be weak allowing a trip when not necessary BUT that is usually not the case unless they have been reset many times in the past.

Make sure all registers are open and that the air filter is clean OR new. Try that then post back with results.