Air Handler blower motor doesn't run


  #1  
Old 06-17-15, 04:55 PM
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Air Handler blower motor doesn't run

Greetings.
Electronics tech w/ 40+ yrs experience...not so much in HVAC.
3 yr old Gibson split system.
Outside heat pump seems ok.
Air handler suspended under house - reasonable crawl space.
Blower motor does not run, hence evaporator coil freezes up.

With power plug disconnected, blower turns freely by hand.
With power plug disconnected, measuring open circuit at motor power jack.

With power plug connected, have solid 240 VAC single phase at the blower motor power plug & jack but no rotation. Not a stall situation, btw.

So, I'm thinking I have an open motor winding, or open starting cap or open starting switch or ?
Going in for another look this weekend.
Taking a clamp-on ac ammeter with me this time...and a camera etc.
Will also be checking model numbers and such.
Sure could use some advice.
Thanks,
Bill
 

Last edited by n4qan4qa; 06-17-15 at 05:57 PM. Reason: More info
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Old 06-18-15, 02:19 PM
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Couldn't get a good look at the schematic last weekend due to accumulated mildew. There *is* a second connector on the blower motor housing. Only 14 of 16 pins have small, maybe 18 AWG white wires whose other ends terminate at a blower board which has 8 small on/off switches, diodes etc. The legend on the schematic may indicate certain functions that are selected by switch settings.I don't think the thing is variable speed but I could be mistaken... don't yet know what lives inside the motor housing.

I remember seeing a small control power transformer and that it was only moderately warm to the touch. Next to the cpt is a control board having a couple of chips and maybe a relay or two.
Didn't have much time to look around due to the need for pawpaw to get cleaned up and attend the granddaughter's birthday party.
Will clean up the Schizmo and give it a better shot this weekend.
The wife says that she just wants the A/C to work.
As for myself, I just want to be the troll who lives under the house learning how all the stuff works - ahhh, living the dream !
 
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Old 06-18-15, 05:18 PM
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You have a variable speed motor.
Many posters on this site claim to have replaced a small part in the motor module for a few dollars to get it running again.

You probably need to pull the blower out of the air handler to access the module.

A few hex head 1/4 inch screws connect the module to the motor.
 
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Old 06-19-15, 02:31 AM
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Many thanks for your comments, Houston204 .
I stand corrected.
This will be even more fun than I had originally thought.
Will report back once the issue is resolved.
 
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Old 06-19-15, 02:50 PM
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OK,
Thinking a tiny bit ahead of my trip down to the Charlotte, NC area tomorrow to
most likely remove the blower assembly from the air handler unit.
Once I've determined which component(s) will require replacing, I'll next be looking for new or refurbished replacements.
No specific model numbers at this point so I just need general info as to how to proceed in securing repair parts, the procedure of which may vary from vendor to vendor.
For example, a friend at work mentioned that he received a decent price, not by being a contractor himself, but by merely dropping the name of one local to his situation.
Any help would be greatly appreciated.
Thank you.
ps
Will have access to this site while in Carolina as well.
 

Last edited by n4qan4qa; 06-19-15 at 03:09 PM.
 

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