Blower doesn't work


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Old 11-23-13, 10:52 AM
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Blower doesn't work

I have a Carries AC unit (model FK4CNF002). Heat pump in the outside works but blower doesn't (tried both heat and cool). Power load (240V) on the blower is there and I also measured the voltage on control board terminals and they seem to have 26V voltages. The transformer (I think), from which a pair of wires go to the blower and another pair go to the control board, feels hot. I am not able locate where the run capacitor is, otherwise I might try to replace it. Any help and suggestion on what I should be looking next will be greatly appreciated.
 
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Old 11-23-13, 12:03 PM
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It is usually the module on the end of your motor that requires replacing.



 
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Old 11-23-13, 12:42 PM
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Thanks. That information sheet is really helpful. So do I need to open up the blower cover to access the modules inside? I am also suspecting that the transformer could be broken.
 
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Old 11-23-13, 01:10 PM
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Turn off power, open the blower panel and remove the high voltage plug from the motor. Restore power and measure for 240 volt AC at you motor high voltage plug.

Turn off power to your air handler and plug the high voltage harness back into your motor.

Remove the 16 pin connector to your motor and then restore power.
Measure for the listed voltage when the listed demand is present.

I used to jumper R to Y1 and measure for 12 volts DC between terminals 1 and 6 with the FV4. This model appears to be slightly different.

If high voltage is present, and the low voltage signals are getting to the motor, it points to a motor problem.

Remove power.
If the motor shaft spins freely, remove the blower housing then remove the motor from it by loosening the set screw on the motor shaft then removing the three 3/8 inch screws holding the motor to the blower housing.

Remove the motor module from the motor by removing two 1/4 inch screws.

Inspect for obvious damage in the motor module. Usually a burned thermister that looks like two quarters taped together with black plastic.

Unplug the motor from the module and ohm the 3 wires AB, AC, and BC.
Ohm each of those wires to the motor housing.
Spin the motor shaft again with the squirrel caged removed.

Post back your results.
 
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Old 11-24-13, 11:19 AM
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Thanks a lot for the detailed instruction. I believe the motor module is broken: the connection between the red wire leg and capacity/thermister seems gone on the back of the circuit board, and/or the three modules soldered on the base of the module are burned (tried to attach an image). Other diagnostics seem normal: 240V is present, 24V between SEC1 and SEC2 on PCB present, 24V between pin 8 of the 16-pin and R terminal on PCB present, ohms on wires going into the motor ok (about 12 ohms). Unless it's just a fix to that broken connection, I'll look to get a new module. Any suggestion where to get them?Name:  photo.jpg
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Old 11-24-13, 11:30 AM
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Probably can't help too much there.
I work for a Carrier factory authorized dealer, so I get them from Carrier.

These modules are programmed for specific air handlers, so I'd be leery of universal replacements.

Do you have a legible module number?
 
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Old 11-24-13, 11:36 AM
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From its barcode ticker, it says GE 1/2HP 02/26/01, and CN02 2KRX. On the circuit board, I see 8794705HGP1 Rev.8 and 50-173102 Rev.J, also a 4900 printed on it. I'll probably solder a wire for that bad printed connection that I believe it needs to be there. Thanks again, you are so helpful.
 
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Old 11-24-13, 12:26 PM
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I was expecting an RMOD44AE or cpn or hd number.

There is a huge thread on ECM motors on this site.
Apparently the components are available a Digikey for 99 cents each.
The module is probably 600 bucks.

Seems like that black epoxy would make replacing a thermister tough.
 
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Old 11-24-13, 04:26 PM
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It's HD something but I have a hard time getting it out of the housing to see the number, probably have to use a puller. If I buy a used motor and module from ebay, what spec should I look for (I guess it needs to work with the control board)?
 
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Old 11-24-13, 06:18 PM
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It needs the correct frame, voltage, horsepower and programming for your unit.
 
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Old 11-29-13, 01:41 PM
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Just found out my motor is HD44AE128. Would a HD44AE116 work as a replacement? Thanks.
 
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Old 11-29-13, 01:55 PM
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http://www.docs.hvacpartners.com/idc...t/40fk-2si.pdf

Take a look at this manual. It does list some other replacements but the 116 is for gas furnaces.
 
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Old 11-29-13, 02:14 PM
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Thanks so much the reply and happy Thanksgiving!
 
 

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