Air Handler

[Stephen P. Shockley]

Hi,

I woke up this morning to my second floor Air Handler not running. The Heat Pump outside is running, yet the Air Handler won't turn on. Any ideas as to what this could be or recommendations on what to do or where to start? I checked the breaker at the unit and it doesn't seem to be visibly damaged in any way.


Thanks,

Steve

[Stephen P. Shockley]

Just an update on my previous post. When I came home this evening I tried turning the fan to the "On" position and then went up to check out the Air Handler. I could hear a humming sound when I got up there. When I pull the breaker of course it stops. So it seems as though the fan motor is seized up. Other than this I don't know what else to do but call a repair person. If anyone has any experience with this I would certainly appreciate their inputs.


Regards,

Steve

[Michael Larson]

See if the fan moves freely when you have the breaker off.

It may be the start capacitor on the fan motor.

It sounds like a repair tech is in your future.

[Stephen P. Shockley]

Thanks for the response Michael. I just went back up there and open the unit back up and check the fan. It does spin freely. Therefore, by your response this sound like a burn't capacitor. Any idea how much effort there is to swapping out a burnt capacitor or is this a simple plug and replace part. This may sound like a dumb question, but what do these capacitors actually look like. I did see two round yellow plastic capped devices behind a panel to the fan, but wasn't sure if this was it. I could post a pic if that helps.


Thanks,

Steve

[Michael Larson]

Originally Posted by sshockley

Thanks for the response Michael. I just went back up there and open the unit back up and check the fan. It does spin freely. Therefore, by your response this sound like a burn't capacitor. Any idea how much effort there is to swapping out a burnt capacitor or is this a simple plug and replace part. This may sound like a dumb question, but what do these capacitors actually look like. I did see two round yellow plastic capped devices behind a panel to the fan, but wasn't sure if this was it. I could post a pic if that helps.


Thanks,

Steve

Size, shape and location vary,

http://images.google.com/images?hl=e...-8&sa=N&tab=wi

[Stephen P. Shockley]

I'll post a pic in the next hour. Thanks, Steve

[Stephen P. Shockley]

Here is the pic that I took. You'll see two yellow components that I was referring to, although not sure if that's what they are. Are the caps typically soldered in place or do they usually have a plug type connection?



Regards,

Steve

[Michael Larson]

The only yellow I see is the two wire nuts and the yellow paint on the temp sensors.

I suggest you find someone knowledgeable with HVAC and circuit diagrams.

The motor for the fan is not in the pic.

If it is the motor humming it probably has to do with the start circuit.

The capacitor provides a push(so to speak) to get the motor spinning.

[Stephen P. Shockley]

Ok, after looking at the pics in the shortcut you sent, I think I've located the capacitors. Looks like they are mounted right on the side of the fan housing. I can't tell if they are soldered in place or not though.


Regards,

Steve

[Stephen P. Shockley]

One more thing. My mistake in my original description. The sound is more of a light buzzing sound rather than a humming sound....


Regards,

Steve

[Michael Larson]

Yes that is a start cap but unless you can determine the buzz is from the motor I doubt if that is the problem.

[Stephen P. Shockley]

Michael,

Update on the Air Handler...

I went and purchased a multi-meter. I first wanted to verify that I was getting the full 240 volts to the unit and that tested fine. Then, I went ahead and dis-charged that capacitor with a screw driver so I could check its capacitance. It was rated at 5 uF and only measured about 0.9 uF. Also, when I went to order a replacement for the unit, the distrbutor looked my AHU model # up and said that the wrong size capacitor was being used. He said it should be a 7.5 uF. That will be here on Wednesday, so I'm hoping this is all that's wrong with the unit. Thanks again for your help Michael.


Regards,

Steve

[David A. Andersen]

That will be here on Wednesday,

Had to order it!

That makes me scared!!!

You don't have to order a cap! They are everywhere!
Hell, go pull one of the junk pile at your local land fill!

[Stephen P. Shockley]

David,

Honestly, I didn't have to order it, but I work a full time as a Lean Mfg Engineer on Boeing Business Jets during the day. So with a 35 mile commute leaving at 7 AM and getting home at 7 PM, there are no stores open around here that I can go to unless I take off of work to pick this up. In this economy, I don't want to do anything that will jepordize my full time job. Also, these distributors won't even sell to me unless I'm a liscensed HVAC repairmen. Hence, my rational for ordering... Plus it is supposed to be a little warmer here over the next few days, so I figured I would wait for it to come in.


Regards,

Steve

[Stephen P. Shockley]

Michael,

Just wanted to let you know that you were correct that it was the capacitor that was the problem. I ended up finding one on my lunch break for $3.29. Put it in tonight and everything was working fine. Just hope it stays that way.

Thanks again for your help.


Regards,

Steve