Performed a diagnostic service call for a furnace that is giving off no heat. The fan is blowing constantly but the furnace is not turning on. The customer did mention, he knows it is probably time for a new furnace and AC, so he is also looking for an estimate on a new system. 28 year old propane furnace not working. I found the high limit was stuck open and would not reset. This furnace is oversized and has inadequate return ductwork. It is a 100,000 BTU input 80 % and only has 4-6 inch returns.
