Help Troubleshooting Compressor

[Mr. Roboto]

Hi All, I have a Husky 60 gallon air compressor, model C602H

This is the compressor: https://www.homedepot.com/p/Husky-60-Gal-Stationary-Electric-Air-Compressor-C602H/205389936

2 days ago, I aired it up and noticed the motor was slow to start. It sounded like the pump was laboring to run too once it was going, as if there was some extra resistance. It aired up and cycled off, but did seem like it took longer than usual. Last night I went out to use it again. Tried to air it up from 80psi tank pressure, and it really struggled to start. It turned over a bit and got slower and eventually was barely spinning so I stopped it.

I let all the air out of the tank and started it with the hose disconnected so it wouldn't build pressure. It was very slow to start and didn't sound great. The oil is right where it should be, and I can hear the unloader letting off pressure when I turn the switch off.

I suspect I need to take the belt off and see if there is excessive resistance in the pump if I turn it by hand, although I'm not totally sure what a good one should feel like. Also, can I run the electric motor without a load on it to make sure it's spinning up OK? I suspect it is. Could it be the starting capacitor, or not, since it does start turning, albeit slowly?

The compressor is bolted to the floor and surrounded by cabinets so It's not the easiest thing to get to, so just looking for some advice ahead of time on what I can check when I find the time to get in there and start diagnosis. I don't have much experience troubleshooting a compressor.

Pic I had of the corner where the compressor lives, for what it's worth..... Thank you very much for any help. This is about the worst time for this compressor to die on me, as I'm in the middle of a few car projects. The compressor is just shy of 4 years old. I bought it brand new, and has only seen light home shop use.

 

[seber]

Yes, the first step is disconnect the belt. No problem running a motor without load. Think bench grinders. That's how they run most of the time. It doesn't sound like a motor problem. I don't know how to tell you about torque. You need to have felt it before to know how it should feel. From the sound of it, I would make an offhand guess that you have a frozen exhaust valve. The good news it that it is an easy fix if you can get parts.

 

[Jswain]

You should be able to turn the belt still attached to both pulled with power OFF and tank drained & drain valve left open.

Should be very easy, if not then remove belt and find out what side resistance is coming from.

If it is start testing the capacitors in the motor and/or the wiring to the motor but it looks like you may have it hardwired? So I'm assuming you never recently changed anything electrically on it

 

[Mr. Roboto]

Thank you both for the replies.

Yes, the first step is disconnect the belt. No problem running a motor without load. Think bench grinders. That's how they run most of the time. It doesn't sound like a motor problem. I don't know how to tell you about torque. You need to have felt it before to know how it should feel. From the sound of it, I would make an offhand guess that you have a frozen exhaust valve. The good news it that it is an easy fix if you can get parts.

Thanks, if I find the pump is hard to turn by hand and there are no obvious signs of the pistons scoring up the walls or anything, I will look there next. I'm not totally sure how to go about testing an exhaust valve if it ends up "looking" good upon inspection, but I will do some research.

You should be able to turn the belt still attached to both pulled with power OFF and tank drained & drain valve left open.

Should be very easy, if not then remove belt and find out what side resistance is coming from.

If it is start testing the capacitors in the motor and/or the wiring to the motor but it looks like you may have it hardwired? So I'm assuming you never recently changed anything electrically on it

Yes, it is hardwired though a fused disconnect. Now that I think of it, there is a fuse for each hot leg in the bar, so perhaps I lost a leg or something? I will verify this first before doing anything else. Next will be checking for resistance, and finally testing the start capacitors.

 

[Jswain]

That would be a good place to start!

 

[bsaint]

After verifying you have a good outlet, Check capacitor(s) with a meter and check centrifugal switch. Make sure both contacts are closing on the pressure switch.

 

[Bert_]

It's not fuses. If one was bad the motor would do nothing.

Could pull the belt, it wouldn't hurt anything. Start capacitor would be one of the first things I would check.

 

[Mr. Roboto]

I verified power to the compressor, that checked out. Also, the caps measured good. The first one wasn’t labeled with a tolerance but from some googling of similar caps, I think the high reading is within spec. Take a look at the attached photos. So, the quick and easy fixes are out, I think.

Gotta move a bunch of **** now so I can get access to disassemble the guard and get to the belt.