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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8135
Experience:  Furnace, A/C and heat pump specialist.
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Fan condenser or compressor? screeching turn on unit: heat

Customer Question

fan condenser or compressor? screeching turn on unit: heat pump split. 3.5 tons r22 ICP
Submitted: 9 months ago.
Category: HVAC
Expert:  airheatman replied 9 months ago.

If motor itself is squealing, issue s motor. Issue could be the hub on the blade. The hub is pressed on and often will become loose.

Customer: replied 9 months ago.
I didnt get to finish my scenario or issue ran out of space.
Here is my skepticism.
1. I put new fan motor on. When I lined up the fan blade through hub and set screwed it to shaft then rotated it to see if the oil and silicone did any good to get the unit up and running sounded good- not great. *** I have a fan blade assembly on order.2. got everything buttoned up and the condenser fan top back up. set thermostate back on 77. put power to the condenser unit (breaker by condenser unit),
Right away the unit screeching again getting very hot- compressor hot !!!!
shut it right down- Now I have heard the SOUND of a locked scroll compressor- ussually a hum so quit sure 89 % compressor is not locked. I would assume I get something. I had the cover on the contactor to see if go sucked in or not.a.) not sure if I need to go out get another capacitor.
b.) I have a kickstart Ks-1 Rectroseal on order coming in Monday- was on the to do list since it makes starts ups smoother.Bottomline- my logic is stuck between- the condenser never made this noise before- so its not a common start up squeal. and it does it right away when I turn on the power ...
Expert:  airheatman replied 9 months ago.

Give me a couple of minutes to digest this

Expert:  airheatman replied 9 months ago.

1. If compressor draws locked rotor it should trip breaker as breaker should only be a 50 or so.

2.Lets do this. Disconnect the wires going to the compressor and make sure they can not touch anything. Then turn on unit so that just fan is running and check two things a. Does it still squeal" b. Does it appear motor is running full speed?

Customer: replied 9 months ago.
okay have to do this after dinner taking a break.
FYI: first squeal incident on thur 9-8 checked the windings on the compressor all had continuity.
Expert:  airheatman replied 9 months ago.

That's fine we will go from here

Customer: replied 9 months ago.
stand by. ...
I will keep the "what to be determined" faulty fan blade off? since I do see the hub is corrodded and what might be hairline stress crack" thus :
1. the NEW fan motor WITHOUT BLADE should not squeal or squeak when powerED ON:
2. Does squeal: compress unplugged then either fan blade CAUSED squeal and or compressor is going?Is my logic correct in why were doing the test
Expert:  airheatman replied 9 months ago.

WE are doing test with fan and blade on but no compressor first.This will determine if squeal is compressor related.

Customer: replied 9 months ago.
1. took blue wire (went to capacitor) OFF, black wire/red wire went to contactor off: all going to compressor.
2. Fan blade back on.
3. turned main panel break on.
4. went side turned ac on thermostate cool- 81 degrees not that it matters. 86 in house in florida nice!
5. went to condenser unit : turned on power:
a. Does it still squeal" : YES!
b. Does it appear motor is running full speed? Kind of.Why. I think the fan blade hub is so seperated that its just spinning ( motor rated 1075 RPM) that its creating the squeal sound. In other words when I inspect the fan blade ON THE FAN MOTOR SHAFT: fan blades SPIN AND THE HUB SPINS!! so the seal has been broken IN OTHER WORDS shouldnt the hub and fan blades rotate/spin together when on fan motor shaft. The "HUB" of the fan blade has nothing to grab two or broken so there indepedent of one in other. The should little higher squeel since I lubed the fan hub assembly with motor oil.Sept 12- fan blade assemby comes in OEM.
Expert:  airheatman replied 9 months ago.

I think replacing blade is going to solve your problem If hub spins. blade will not turn fast enough to move enough air across coils therefore unit runs a high head pressure heating up the coil and compressor.

If you have further questions, please let me know.

Thanks for letting me work with you.If my answer has been polite, professional,and thorough, please click one of the ratings before you go. If you still need help let me know!.Expert is not paid for assisting you until you rate answer.Feel free to follow up for 30 days at no additional cost. Bonus always appreciated if you feel justified.

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Customer: replied 9 months ago.
Could you stand by until Sept 12 when the part comes in and I install (will install same day- family is hot!)- then confirm everything went smoothly and were up and operating again?- much appreciated!
Expert:  airheatman replied 9 months ago.

Absolutely.If you do not mind it is best to go ahead and rate my answer.After doing so, we have 30 days to work on the problem and follow up at no additional fee.I am here to help you get issue completely solved. Problem with waiting to rate s if question is not rated within a few days, it times out.Thanks again .I look forward to follow up.