Air handler not pushing enough air

dcastillo

Doc, you seem to know your stuff....

Tenant said I can come by tomorrow evening...
While there I plan on cleaning the inlet side of the fins (bough a cleaner from HomeDepot) then will use a spray bottle to spray water to ensure all the cleaner is gone and finish off with a shopvac with brush attachment...

Ill also verify the current and voltage being delivered to the motor.
Am I correct in assuming if the voltage is low the circuit board is possibly bad, if the Current is high, then the motor is probably bad?


Ive been trying to locate a replacement motor just incase, but having a hard time figuring out the exact one I need

i found these three that seem correct
http://www.americanhvacparts.com/Mer...ode=MOT39GE232
http://www.americanhvacparts.com/Mer...de=MOT24251190
http://www.americanhvacparts.com/Mer...Code=MOT33GE23

but not sure how to verify...
attached is a picture of my airhandler, can you advise of if I am specking out the correct motor?

Attached Thumbnails

 

Doc Holliday

What's sucks is that my cell phone took a poop on me yesterday or I'd call the local Trane supply house and with the use of your model and serial numbers, find out exactly what motor to use.

On a condenser fan motor you can see the sticker with the HP (horsepower), the rpm and the electrical supply. You'd have to literally pull the blower motor out of the air handler to be able to see the sticker on an air handler's motor. Other than that, use the model and serial numbers of the actual unit.

Can you take a picture of the control board? Does it have speed taps or is it the pin type? There are different color wires going to the motor itself. One will be used for cooling, one for heat and one for fan and most likely an extra will be "parked" on the board, unused.

If pin connection you need to see, if you can on the motor, which wire is being used for which call. Then check the pins for voltage by removing the actual pin harness connection and checking each individual pin for voltage while the unit is on call for either cool or heat or fan. Make sure you have the door switch taped in or the unit will have no power. You can pinpoint which pin is being used for cool or heat this way and then simply put the connector back on see which color wire lays on that pin. That will tell you which wire is being used for which call to the blower motor.

All a control board does is by way of low voltage direct the "traffic" of the high voltage. On call for cool, the high voltage should go through only one high voltage pin/spade on the board to the motor. On call for heat, a different pin/spade terminal.

It's much easier to do if the board has spade terminsal with cool, heat, fan or hi, med-hi, med-lo, and lo.

Can you take pics of the board?

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Thanks.

Doc Holliday

But yes, the board needs to be receiving full voltage and it needs to be sending full voltage out of it to the blower. You check the incoming power at the furnace and the outgoing on the pins or spades to the blower. It should be the same.

If you have a clamp meter, check the amperage draw of the motor and compare it to what the motor calls for. Again, we'd need to be able to have that information which Trane does but my phone is dead. Sorry.

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Thanks.

dcastillo

I will try tomorrow....
thanx again
-Danny

beenthere

All three of those motors are condenser fan motors, not air handler motors.

Can't remember, have you checked the run capacitor yet.

dcastillo

yep, replaced it last week....

when I get there tomorrow, Ill just try and pull the blower assembly out and get the exact model off the motor, just incase its the issue....

Doc Holliday

Blower motors are easy. Have 1/4" through 1/2" nutrdivers and or wratchets with you. That'd be 1/4", 5/16", 3/8" and 1/2". Those are the common sizes of the individual screws and bolts to remove and dissassemble blower motor assemblies completely.

And a good flashlight.

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Thanks.

dcastillo

just remembered... while Im in there, ill try to find the 1/4" socket i dropped last time

Doc Holliday

And a medium size (8" would work, or 10") adjustable wrench to loosen the blower wheel screw and to hold onto the blower motor shaft. DO NOT TAP ON THE END OF THE SHAFT OR YOU"LL MESS YOURSELF UP! Use some WD-40 or if you have to automotive or household cooking oil even and add some into where the screw on the blower housing attaches it to the blower shaft (you'll have to completely remove the screw and pour it into the hole), hold the shaft of the motor with the adjustable wrench (one side at minimum will have a straight edge), and twist the blower wheel. It'll loosen and slide off.

If you tap on the end of the motor shaft you'll be needing to cut it to remove it from the blower wheel.

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Thanks.

beenthere

Now we know whats slowing the blower down. LOL... J/K

Doc Holliday

HA!! For the WIN!!

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Thanks.

dcastillo

So here is what I found/did tonight....
First got access to the fins and vacuumed both sides (inlet and discharge) with a brush attachment.
Then sprayed it with some coil cleaner, let it soak, sprayed it with a water bottle.... then repeated... then vacuumed it after if dried
I then removed the blower assembly to try and get the model # of the motor...but it was hidden under hte bracket that goes around it, even tried to disconnect the squirrel cage but it wasnt happening... and I was pressed for time so I jsut took a bunch of photos and hopefully that can identify the model I need (If I need one)
I then put everything back together and verified the voltage to the entire blower assembly, it was about 243.
I then verified the current draw to the motor at about 1.2Amps (well under the 1.7Amp rating on the front of the unit)
Also, someone (Doc?) was talking about checking the ciruit board while different things were being ran to see different speeds or something.... after looking at my system (and talking with an AC Journeyman that the tenant hired to put in the thermostat) there are only to positive connection points (red wire) to the motor, medium and low speed (high speed doesnt have a spade). So it would appear the only way to vary the speed of the fan is manually moving the wire.... but its currently on the highest possible setting....
Unfortunately I had to leave in a hurry before the guy finished putting in the thermostat to try everything out... so I will call her in the AM for an update....

Hopefully the problem is solved, cause Im out of ideas....

Is it bad to replace the motor with a stronger model (possibly higher RPMs) in order to increase the air flow some? Or would that mess up the entire balance of the system....
thanx for all your help...
I think (as a new homeowner) I may have to start hanging around this forum more for all the great advice...
Maybe layoff the Android Forum I normally hang out in

-Danny

beenthere

The blower motor is a 1075RPM motor. A higher HP higher RPM motor wouldn't help much if any, unless if was about 60% higher speed, which would mean the motor would need to be about 4 times the HP of the current motor.

Is the black wire connected? Its the high speed tap.

dcastillo

There were only 2 wires going directly to the motor windings, black and yellow. teh other ends went to each side of the cap...
then there was a red wire coming straight from the contactor/relay and that could be plugged into either A (low) or B (med), there was no C on my motor.
There was a third wire on the capacitor (the first two went into the motor coils) connected to the same capacitor terminal as the black wire to the windings, and I beleive it went back to the circuit board area...

any thoughts?
I have a few pictures of the motor, circuit board and schematic if that helps...

thanx again, Ill call the tenat this AM and see what she thinks.
Danny

ryanxo

I went into mine yesterday and took the box out that has all the wires that run to the thermostat on it and looked inside and there was nothing in there that indicated choosing airflow speed. After tracing the schematic though I followed the wires running to the motor. There are 4 slots/clips to put wires on and according to the schematic A was Low, B was Med, and C was high. There was a red and a blue running to A and B. So i took those wires and moved them to B and C.

Good news is when I turned my AC on and cranked the temp down a few degrees the air flow was about double the trickle it was before.
Then I turned it off and let the system turn off.
Bad news is that when I turned it to heat and cranked the temp up a few degrees above what it was in the house...there was nothing.
So then I turned the fan from Auto to On and it came on.

I'm guessing that C aka high speed does not work on my motor.

Which wire controls which btw? I assumed Red for heat and blue for cool because it wouldnt make a damn bit of sense for them to make them that color then reverse it unless they were just trying to screw with DIYers.



dcastillo:

I may not be an AC pro by any means but I am a Google pro and I used those skills to find you this!
http://www.myhvacparts.com/store/tra...o2615.php#1130 and it says it fits TWV024A140A0 with about 80 other models so I thought it might be a good shot.

They also carry the motor that fits mine which I'll include for future reference for any poor souls that have the same issues.
MOT02611 Trane 1/4 HP Air Handler Blower Motor (MOT02611)