Goodman heat pump - blower motor run capacitor failed twice, what's wrong?

[toocoolforschool]

Something has - I think - destroyed the motor run capacitor on my heat pump, but I am not sure what it is.

Back story:

I have a Goodman 3.5 ton heat pump, model ARUF036-00A-1A. Two nights ago I woke up to the smell of something electric burning, and the sound of the blower motor stalled while trying to start.

The motor run capacitor is a 7.5uf and 370v, part number 27L566. I picked up a replacement capacitor, which is the same except it is rated 440v/370v at the recommendation of the local HVAC shop. This is a Mars #12931. I installed that, turned the HVAC power on, and it worked fine.

At that time I noticed a transformer (see below, left side) in the air handler was buzzing, and I don't recall it making any noise before. I looked at it, and the fuse that is installed was not blown, so I buttoned things up.

Last night I again woke up to the smell of something electric burning and a stalled blower motor. I turned the power off to the heat pump.

I took photos of the heat pump innards, CLICK to get full-sized image:

Transformer on the LEFT is buzzing:



Motor run capacitor:



Can someone tell me if this is a simple fix - is the transformer? Computer board? Or do I need to call someone?

Thanks!

Thought you'd appreciate an update - the technician diagnosed the blower motor had failed. It has ... uh ... one of the windings grounded out. Basically, it is shorting out. In addition, it spins very poorly. I've ordered a new one and will have it installed.

He also discovered that it was the wrong sized motor. The motor is one size too small, which he says can cause premature wear because it's working too hard, and additionally it causes poor airflow. Poor airflow has been a big issue since we moved in, so hopefully the correctly sized motor will fix that, as well as better heat/cool my house.

Why would the motor be sized wrong? I am sure you did not order the OEM replacement for the unit. Remember when trying to save money you will usually end up spending more.
I think we let this one get to out of hand.

[Jessie james]

Ditto on Jblack's post. Call a pro, and bite the bullet. Did ANYONE check the RPMs on old motor?? I'm assuming you got new motor over internet? They have a special "warranty" on them motors I'm sure........

JD, Wahoo, you are both offering sound advice. I'm just a little put out. I do have the tech scheduled to come out and look at it. They were nice, I can't imagine they'd be rude.

The last motor was clearly toast, it would barely spin. Yes, I ordered the new motor online here:

Links to direct purchase sites are not permitted here.

I just can't see how I screwed up the install. It's trivial. Unscrew the set screw from the blower fan that attached to the motor shaft. Unbolt three bolts from the old motor. Slide old motor out. Swap metal bushings from old motor mount holes to new motor mount bushings. Slide motor in. Install bolts. Be sure set screw is on flat edge of motor shaft. Install set screw on blower fan to motor shaft. Slide housing into air handler and bolt it in. Wire using existing wires which match identically. Test.

The motor ran fine for a day, at least 10 hours of use. Suddenly on the start up yesterday afternoon it sounds like someone dropped a rock in the motor.

Yeah, in the end I probably ruined it somehow. That's okay. At least I gave it a try. I'd rather break something and learn a lesson than not. So I'm going to be broke for a month, nothing new. That's life!

[Jessie james]

jessie,
The burned wire was caused by a bad connection which caused resistance locally and high heat which melted the fitting and ends of the wire and not related to your motor issues. The new wire and good fitting connection should be the end of that problem. That loose connection did not cause increased currant flow (amps) so the breaker would not protect the wire in that case.

Thanks for the explanation.

Can you get a view of the blower squirrel cage and watch it while it is running to see if it running true in the blower housing and not wobbling?

Ok, I did this. It is very hard to tell if it's not centered or is loose. I grabbed the cage and tried to move it every which way and it seems as solid and as tight as can be.

Watch it when it is spooling down so you can see better. If the blower ran fine without noise the first day than something has changed since then. I would start by checking the attachment of the squirrel cage again and make sure that is not loose on the shaft and hitting the sides of the blower housing or just flexing on the shaft.

It's not hitting the sides, it's about 3/4" away on each side. I was careful to be sure it was centered in the housing for that very reason.

I have seen the actual squirrel gage break. With the power off give everything a tug and shove. If everything looks and feels normal and it still makes that noise and vibration you can remove the assembly and dismantle it and run just the motor by itself and see if the problem goes away. Make sure that the motor shaft runs perfectly true because anything but perfect will make the cage wobble and produce vibrations at speed. I would bet it runs fine and smooth and the issue is with the cage and its mounting. Make sure nothing is inside the cage and causing it be unbalanced ( are you missing a glove?)

I may do that. No lost gloves! Haha.

Good on ya for learning about you equipment and learning how to maintain it and I wish you a merry Christmas and a warm house.

Thanks very much!

Well, now get this. After I yanked and tugged and etc., the noise is gone! Somewhere a screw or a bolt is loose, and it's probably in the 6' 4" tall, 180 pound homeowner ...

So, I'm an idiot (like someone's signature on this thread mentions) and installed it wrong somehow. I am going to let the techs come fix it proper.

[jtrammel]

The squirrel cage has balance weights on it to keep it from wobbling, its easy to knock one off or misalign one when reinstalling a motor. Also the band or ears that hold the motor in should have some type of rubber washer to prevent vibration of metal on metal.

[Jessie james]

Update: I removed the set screw from the cage/shaft, repositioned the cage slightly, tightened it back up and now the noise is gone.

Question: There is still a small amount of vibration present. Is this normal?

[Jessie james]

The squirrel cage has balance weights on it to keep it from wobbling, its easy to knock one off or misalign one when reinstalling a motor. Also the band or ears that hold the motor in should have some type of rubber washer to prevent vibration of metal on metal.

What do those weights look like? When I was taking it out, a white plastic washer (broken in half) fell out of the blower motor housing:



The rubber grommets are in place, and the metal bushings from the old motor grommets were moved to the new motor.

[beenthere]

Strange thing though. Is you installed the wrong motor if you put a 1/2HP in.

That tech was wrong about what size it should have.

[jdblack]

You said you called the tech but you still continue to work on it and go against our advice. This is clearly too much DIY .....

You're going to forget to pull a disconnect and wind up face down or have a blower start and Yank a finger off.

Stop now!


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[wahoo]

That "white plastic washer piece" looks suspiciously like an insulator bushing from your heating elements. Hope it's not and I'm wrong. You might keep it and show it to your tech when he comes out.

[jtrammel]

That "white plastic washer piece" looks suspiciously like an insulator bushing from your heating elements. Hope it's not and I'm wrong. You might keep it and show it to your tech when he comes out.

Is it ceramic or plastic OP? That is not a balancing weight, they are little metal clips.

[toocoolforschool]

Strange thing though. Is you installed the wrong motor if you put a 1/2HP in.

That tech was wrong about what size it should have.

That's the point I was trying to make but like most of my posts it was ignored. Sometimes people only hear what they want to,
Everything else is just blabber.

[Jessie james]

You said you called the tech but you still continue to work on it and go against our advice. This is clearly too much DIY .....

You're going to forget to pull a disconnect and wind up face down or have a blower start and Yank a finger off.

Stop now!

Take a deep breath, it's going to be okay! I'm very competent at electrical, mechanical, and other items. I've plenty of experience around gas & electric motors, high voltages, capacitors, fan blades and the hazards of fingers and loose items of clothing. I just don't happen to understand exactly what is going on here and wanted some expert advice to round out what I already know.

Is it ceramic or plastic OP? That is not a balancing weight, they are little metal clips.

Ceramic.

That "white plastic washer piece" looks suspiciously like an insulator bushing from your heating elements. Hope it's not and I'm wrong. You might keep it and show it to your tech when he comes out.

It probably is. Time to have the heat pack checked out too.

That's the point I was trying to make but like most of my posts it was ignored. Sometimes people only hear what they want to,

Everything else is just blabber.

I didn't mean to ignore your comment about the motor, but you didn't says what the ramifications are. Fire? Death? Destruction? Today is the end of the world after all, does it start in my utility room?

[toocoolforschool]

I don't want to get too negative but if you have so much experience why all the problems.
No it dosen't start there but in your wallet and you family looking at dad like he has lost his mind.

Ceramic.


It probably is. Time to have the heat pack checked out too.


I didn't mean to ignore your comment about the motor, but you didn't says what the ramifications are. Fire? Death? Destruction? Today is the end of the world after all, does it start in my utility room? [/QUOTE]