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dieselburner 02-28-2012 09:03 AM

Remove blower motor on Convertible Trane (American Standard) Air handler
Hi, I have a 3.5 Ton Convertible air handler made by American Standard. It is in the right horizontal configuration. The blower motor is malfunctioning so I need to pull it but I do not see how this unit comes apart. I do have the access panel off and I have cut the power to the unit and disconnected the motor wires. Has anyone here done this task or have any directions on how the blower assembly is removed? Thanks in advance. Steve

thermalmedics 02-28-2012 09:31 AM

blower motor
After pulling power to the air handler discharge the run capacitor for the blower motor. Just use and insulated screwdriver and touch both terminals WHILE HOLDING INSULATED HANDLE.

TAKE PICS OF EVERYTHING. I still do this on wiring setups to this day

Note wiring setup you can draw it out or even leave them attached for now.

Open the case with a hex driver probably a 5/16ths bit.

You will see a squirl cage motor with the blower motor in it.
You remove the whole squirl cage assembly. Its not hard just a few screws holding it in and then the whole assembly slides out.

remove mounting bracket from squirl cage and remove set screw from motor shaft and get the old motor out. this can be a PITAzz if it has been in there for eternity and there is a killer tool for it called 'the ultimate fan puller' or something. you can get it out too with some work usually and maybe some oil.

replace, remount and get set screw on FLAT side of new motor shaft. it cannnot slip.

rewire and run with a hand on the disconnect to make sure it spins nice and easy.

oh yea your new motor may have three or so speeds (lo, med, hi) so you will have some excess wires (2)at the end. this is normal.

Just curious,
you are sure it is the motor right, not a run capacitor or fan relay? just an expensive part and PITA if you dont have to .

take care and good luck

thermalmedics 02-28-2012 09:51 AM

short version

sorry, short version not the novel...

remove squirrl cage assembly and it all slides out

dieselburner 02-28-2012 11:57 AM

Just curious,
you are sure it is the motor right, not a run capacitor or fan relay? just an expensive part and PITA if you dont have to .

take care and good luck[/QUOTE]

Well, what it is doing is it starts up and runs normally for about 3 seconds and then there is a godawful noise and the unit stops spinning. I am guessing it is the motor and not the cap since it starts ok?

thermalmedics 02-28-2012 12:56 PM

couldnt be the metal grinding
its not the metal grinding from the squirl cage fan is it? ive heard a lot of godawful and that is definately one you dont forget.

once the blower motor gets up to speed maybe the inner squirl cage is touching the housing. If the mounting screws (and housing) for the blower motor is/are loose and there is any play you get a godawful sound.

if the motor bearings are goin out and the motor sings than yea i'd replace the motor.

you can test it by

a)manually moving the motor housing to see if there is any play in it


b)re-create event and be a spectator

1.pulling power to the air handler.
2.setting the thermostat fan setting from auto to on
3. applying power back to airhandler with the cover off (AND ANY BODY PARTS YOU ENJOY WELL CLEAR) and listen for the sound.

might clear it up for you

good luck either way

dieselburner 02-28-2012 07:01 PM

OK, I got the blower assembly out and removed the motor from the wheel. Sure enough, the motor sleeves are shot. I am going to replace it with a ball bearing type motor. I spec'd one out on Grainger part number 4M207 that looks like it will work fine although it is listed as a condensor drive motor. It is 1/2 horse cw or ccw, is rated up to 60 degrees C 230V and has the proper motor and shaft diameter. It only has one speed but I am only using the high tap anyway. The shaft is longer than it needs to be but will still be in the blower housing. What do you all think?

thermalmedics 02-29-2012 09:24 AM

would work
The motor will probably work ok for awhile. Just curious why you dont replace it with an actual blower motor?

The two motors are cooled differently via airflow. Blower motors have openings on the side as the air is pulled across them into the squirrel cage and condenser fan motors air is pulled vertically through them.
You could have a mounting issue too. Anywho its your dollar in the end, I have changed a few hundred and have never done it or would.

dieselburner 02-29-2012 09:43 AM

I ordered the new motor last night along with a new run cap. The reason why I went to the different motor is that it has ball bearings. I had the same issue about 15 years ago in another home where the sleaved motor went belly up. I spec'd out a motor that was nearly identical except it had real bearings on the shaft and it ran quieter and longer than the first one. The first motor only went 3 years. We were in that home 8 years after I swapped out the motor and it was working fine. The motor diameter is identical so the mounts are the same. As far as the air flow, this motor has the same cut outs as my old one and the one I specd has a 20C degree higher rating than the old one. As far as I know its still running. I am going to install my new motor tomorrow evening hopefully. If it gets here that soon. I will let you folks know how it works.

dieselburner 03-01-2012 06:50 PM

Up and running! Nice and quiet too.:banana:

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