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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Fan on havac condensor turns slowly and intermittant buzzing

Customer Question

Fan on havac condensor turns slowly and intermittant buzzing coming from unit. I checked contactor and capacitor both good. Fan turns slow even when off at thermstat
JA: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?
Customer: Don' t know.
JA: Do you plan on doing the work yourself?
Customer: That depends. But I like to check as much as possible so if iI call a tech i don't get parts replaced that i don't need. System is just a little over two yrs old
JA: Anything else we should know to help you best?
Customer: no
Submitted: 27 days ago.
Category: HVAC
Expert:  airheatman replied 27 days ago.

If fan is turning with no call for ac, we have a voltage bleeding for some reaon.Do you have a volt meter for troubleshooting?

Customer: replied 27 days ago.
I do have a volt meter.
Customer: replied 27 days ago.
i do have a volt meter
Expert:  airheatman replied 27 days ago.

Great.Give me model on outdoor unit so I can guide you in determining where we are getting the voltage to fan

Customer: replied 27 days ago.
14AJM24A01 RHEEM 2 TON
the compressor is not coming on either just an intermitant buzzing while fan turns slow
Expert:  airheatman replied 27 days ago.

OK I want you to start at contactor with thermostat OFF.

Check both sides of contactor and tell me if we get voltage on both sides

http://i.imgur.com/pT2mWjq.png

Expert:  airheatman replied 27 days ago.

See below

Customer: replied 27 days ago.
240
Expert:  airheatman replied 27 days ago.

Both sides and thermostat off?

Expert:  airheatman replied 27 days ago.

Look closely at the contactor and see if plunger is pulled down,possibly contacts burned together.Then remove one of the smaller wires on side of contactor and see if we still get 240 on both sides.

http://i.imgur.com/cQG4hdG.png

http://i.imgur.com/IDWvQJW.png

Customer: replied 27 days ago.
Both sides? Thermostat has only one button for
cool and heat and off
Expert:  airheatman replied 27 days ago.

Both sides of contactor

http://i.imgur.com/pT2mWjq.png

Customer: replied 27 days ago.
240 on one side and 120 on other. Plunger is not down and can is moving slow with buzz every 20 seconds. Thermostat is off
Customer: replied 27 days ago.
Correction fan is moving slow
Expert:  airheatman replied 27 days ago.

Next check between the orange C terminal on capacitor to ground lug

Customer: replied 27 days ago.
No voltage
Expert:  airheatman replied 27 days ago.

OK if fan is turning with no voltage to orange you most likely have a bad fan motor. If you push contactor plunger down will compressor come on?

Customer: replied 27 days ago.
No
Expert:  airheatman replied 27 days ago.

OK turn thermostat to cool and see if we get 240 between the wires coming off of contactor

Customer: replied 27 days ago.
Ok game started I will get back to u
Expert:  airheatman replied 27 days ago.

OK