hi, i think you should have changed the high limit stat first and not the over heat stat as that is more likely to give that symptom. if you know how to use a multimeter, put it on the overheat stat first, black to incoming neutral terminal and red to both sides of the overheat stat terminals (one at a time!) to prove voltage in and out of it, that will prove the o/h stat is working correctly. if you are insisting on doing the repair yourself then change the h/l stat as a rule first as they are quite cheap, and re-try. this sort of fault can also be cracked or fatigued silicone tubes between the air switch and the fan, which lose/gain vacuum/positive pressure with variation in temp. cheap to change and another possible out of the way. these are safety devices and should be tested by a qualified engineer, if in doubt after the stats, stand back and make the call as the air switch is in the combustion chamber, usually, and that is a no-go area for diy'ers. buy a co1 alarm too, they dont cost much!!!!!!!
nickfromwales!, January 2010
