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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22680
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have an American Standard Freedom 80 model #AUD080C936H4.

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I have an American Standard Freedom 80 model #AUD080C936H4. The blowler motor makes a humming sound but does not start.

When the motor hums, have you tried to hand spin it to see if it then takes off and runs?


Customer: replied 4 years ago.

yes. It spins freely but won't take off


Thank you,

Usually if it takes off when spun it is the capacitor
5 Mfd 370 Volt Oval Motor Run Capacitor

But in your case it could be either the motor or the capacitor.

Since it hums we know it has power. Now it is just a matter of if the capacitor or motor is at fault.

You could replace the capacitor first. (cheap and easy) and if that fails move onto the motor. If the motor is bad the capacitor needs to be replaced anyway.

I am available for follow up if you have a meter with a microfarad setting and wish to test the capcitor

Customer: replied 4 years ago.

I don't have a meter with microfarad. Just for clarification, humming = power, no need to check the board? Any idea of ballpark figure for that type of motor?

If the motor hums it likely has power.

If you like you can measure the wires to motor to verify 120v.


BillyHvac and other HVAC Specialists are ready to help you
Customer: replied 4 years ago.
Hi Billy,

I replaced both the motor and the cap and still same noise. fan turns very slowly and motor heats up
Do you have a meter?

Or we can wire direct as a test.

Customer: replied 4 years ago.
i Have a voltmeter. However I wired the motor direct to the on/off door switch with the same result.
What is the power being supplied to the motor via the door switch?

Customer: replied 4 years ago.
115 vac
Please tell me what wires from motor are connected to what terminals.


Customer: replied 4 years ago.
black to cool, blue to heat, yellow to park, red to park and white to cir
Do you have a circN, or Neutral? Thw hite wire should be on a neutral with other white wires...
Customer: replied 4 years ago.
It is on the neutral side of the white rogers 505A50-473. Just removed all but the black wire and white wire direct wired to switch and the fan ran backwards at hi speed
Thank you,

does the new motor have the directional plugs to change rotation?

Customer: replied 4 years ago.
I don't know if it does. I can give you the grainger model number if that would help, otherwise I'll need to remove it to see. It ran in the right direction with everything hooked up just slowly.
Grainger number will is the capaicor hooked up?

Customer: replied 4 years ago.
the motor is actually a Dayton 3LU79J. The cap is hooked up with the wires provide from the motor. One wire brown and the other brown/white but the cap does not indicate any specific way to hook up and I've tried it both ways.
At the rear of the motor are ther 4 shorter wires attached to each other?

Customer: replied 4 years ago.
there is what appears to be a small cylinder shaped object with white and black wires coming in from both ends.
Thank you.

Unplug the cylinder at itss center connection point. Then turn the plugs so the position is reversed.

Then try unit again

Customer: replied 4 years ago.
the motor is now working full speed with the wires in place but still turning backwards.
And you reversed the plug?

Customer: replied 4 years ago.
yes, its weird because before I got only a hum and/or slow speed with all wires connected and now it goes full speed but wrong direction with all wires connected. I even tried to reverse it back and got the slow speed again.
Ok, is this motor capable of 115v or 230v?

Is there a line drawing on the box or the motor identifying reverse?
Customer: replied 4 years ago.
the box says 115v and gives no indication of reverse.

with just the black and white hooked up....then by swapping the plug connection we should have reversal.

Can you hook the white and black direct and bypass the module totally?

Customer: replied 4 years ago.
direct wired and still wrong direction
when you reverse the plug whaat happens now?

Customer: replied 4 years ago.
still wired directly or back to through the module?
wired direct
Customer: replied 4 years ago.
still the wrong direction
Customer: replied 4 years ago.
yes that's what it looks like
so on the revere plug..with combination blacks to blacks....or black to white rotation does not change?

Customer: replied 4 years ago.

you are not going to like this especially given your challenges thus far.

1) If the motor will not run while hooked to the module, the module may be energizing more than one terminal at a time. We know the blower motor runs with module bypassed.

HOWEVER - your motor is not respondin to the reverse plug. This is not a in depth thing to convert. as you ee the plug simply swaps to reverse rotation. But yours is not working.

I really am sorry you have so much going on...but right now I would tke the motor back and swap it...they can even bench test it to confirm.

Then I would replace the module, or at a minumum do not hook anything more than black and white.

Customer: replied 4 years ago.
ok, thanks for the help. I will see what I can do at Grainger.
Just respond back here as you are ready to proceed

Customer: replied 4 years ago.
Thanks for your help Billy, I returned the motor to Grainger and although they said they don't test motors, they gave me a new one. When I hooked it up it ran and all is well. Thanks again.
Excellent news!

Thanks for sticking with me.