MILL123

I have a pair of Amana 90% efficient gas furnaces model #'s GUC045B30B which were installed in 1990. On one of the furnaces, the blower does not go on half of the time. The electric ignitor ignites, gas is released & the furnace heats up. It then attempts to start the blower but half the time the blower never starts up. It sometimes makes (3) attempts or so & then shuts down. The wheel inside the blower moves easily & is not stuck. Could this problem be caused by a faulty switch or relay? Any help is appreciated.

Thank you.

kok328

It could be a faulty switch or relay. It could be a bad contactor, it could be a bad fan motor capacitor, it could be a bad limit switch or it could be a bad fan motor.
Only handson troubleshooting will yield the correct answer.

bwood316

furnace ignitor not coming on and blower not coming on as well

Wuzzat?

The voltage across the closed blower motor relay contacts should be less than 0.1V.

Post a schematic and we can step you through it.

Do not replace parts by trial and error; sometimes it's just a corroded connection that you can fix with fine sandpaper and sometimes the new parts will immediately burn out because you haven't found the root cause.

BTW, one forum survey had the avg. residential HVAC lifetime to be 23 yrs, with a max of 80.