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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Just confirming my suspicions. Central unit blower motor wont

Customer Question

just confirming my suspicions. Central unit blower motor wont start. it just humms and will barely turn. figured it was the motor or the starting capacitor. too loud for circuit board noise i believe. the only way to stop the noise is to unplug unit or remove cover. t-stat wont stop the motor from tryinh to start
Submitted: 2 years ago.
Category: HVAC
Expert:  Tim H. replied 2 years ago.
Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need.
Are you talking about your furnace blower or outdoor fan?
Customer: replied 2 years ago.
Furnace blower
Customer: replied 2 years ago.
Outside compressor fan motor working as it should
Expert:  Tim H. replied 2 years ago.
If you go down to the fan with furnace off, does it spin freely?
Customer: replied 2 years ago.
It spins freely with no power to it! When the safety button is pushed in it has some resistance to turn! But will still turn by hand
Expert:  Tim H. replied 2 years ago.
It sounds like a bad blower motor. Do you have a voltmeter to confirm voltage to it?
Customer: replied 2 years ago.
I do have a voltage meter with me but I'm not at the unit. What voltage should I have at the contacts?
Expert:  Tim H. replied 2 years ago.
If you call for cooling, go down to the unit board and find the terminal where the high speed blower lead attaches, usually a terminal marked COOL or something like that, then we would test for voltage from the COOL terminal to one of the white neutral wires. Blower door switch should be pushed in when taking reading and voltmeter set to "volts AC". We should read 120 volts.