Originally Posted by R-SOLO
I've changed everything but the t-stat
Evidently the problem lies elsewhere or there is more than one problem.
A temporary fix for this involves the mixing together of 1 part rum and 3 parts Coca Cola.
The root problem may not be in the furnace after all, it could be a power quality problem causing a failure in the furnace.
In a properly designed and built unit all parts are equally likely to fail. If not, there may be a factory-published Technical Service Bulletin detailing the design defect and the recommended fix.
-Educated guess (you might get lucky) or
-Uneducated guess (may be costly and it still isn't fixed) or
-you take a reading, decide what it means on the spot and proceed from there (reduces uncertainty in deciding what the problem is), or