80 Gallon CH compressor runs fast/slow

by Blake
(Lehi, Utah, USA)

Campbell Hausfeld 80 gallon air compressor

Campbell Hausfeld 80 gallon air compressor

I've got an 80 gallon CH compressor that I've had for about six months. I've put probably 5-10 hours on it in that time and it has been running great. Output has been fantastic and no issues before now.

A couple of nights ago I had a session on my sandblaster where it was running frequently over the course of an hour or so. Towards the end I noticed a lot of condensation in the air and the flow seemed to be labored, but the compressor sounded like it was running fine. I finished up my project, emptied the moisture trap and tank drain and blew out the dust in the garage without issue (the compressor ran one more time).

Tonight I went out to start it up again and it seemed to start a bit slow, then sped up then slowed down again. This happened several times over about 30 seconds to a minute, so I shut it off. I tried to cycle it back on three or four times, however each time it did the same thing.

Additional info: the motor wasn't hot at all and no electrical smell, but the pump got hot quickly. The oil is used, but still clear enough to see the dot in the sight glass. I will change it in the AM & see if that helps, but I'm not hopeful. The unit is hard wired (wired directly into the power box on the house) and is the only thing on the circuit.

Comments for 80 Gallon CH compressor runs fast/slow

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Sep 22, 2014
Motor test
by: Doug in s.d.ca

Not much you can do as far as voltage without knowing the wiring.

Audibly, it should run steady and quiet. It may run up and down, and if it does that is a sure sign of cap or centrifugal switch problem.

It's possible it'll run fine, but you still have a cap related problem. You may find a loose or broken wire in the motor cap housing.

Sep 22, 2014
by: Blake

Agreed, thanks for the great help!!

I'm going to run the motor off-load today to see what I get. Should I be checking for a particular voltage output somewhere or just listen for the motor to speed up/slow down as it has under load?

I read the capacitor testing page and will try that later today as I get time as well.

Thanks again!

Sep 21, 2014
Thanks Doug & Buster
by: Bill

Hey guys, thanks for working on this for Blake and others. Your experienced input is very much appreciated by all.


Sep 20, 2014
by: Doug in s.d.ca

Then I think you should definitely check those motor caps and switch.

They should not be bad this early, but it sure sounds like something is off.

You can check the belt tension while you're at it. Probably a bit loose.

Sep 20, 2014
Sluggish motor
by: Buster

Hey Blake, I agree with Doug about running the motor with the belt off and see how it does, or bleed all the air from the tank and run it. Sounds like a motor problem. Let us know the results.

Buster in L.A. (Lower Arkansas)

Sep 20, 2014
Todays troubleshooting
by: Blake

Thanks Doug. I changed the oil today and it was dirty in the bottom, but didn't look bad IMO based on engine oil I've changed. It didn't smell burned or unusual either.

It did get a proper break-in and has been running great until now.

I refilled the oil with a synthetic blend compressor oil from Lowes and cleaned the intake filters as well. I also started it with the filters off to check the suction and both cylinders are pulling hard.

One thing I noticed: previously when it would start up it would chirp the belt as the motor kicked on. Now, it comes on at about 60% normal speed, then slowly winds up to about 80-90% normal and will then fluctuate between about 30% and 80% of normal (just guessing based on sound).

The auto shut-off is working and the tank is filling, just at a slower pace than it should.

Sep 20, 2014
Motor mystery?
by: Doug in s.d.ca

The compressor heat is likely normal, but you may wand to check the filter and check valve between the heads.

You're right about the oil, but good to change anyway (did you do a break-in when new?)

Possibly, the pressure switch is going bad (contact burn or the like).

See how the motor runs with no load, and maybe check the caps and centrifugal switch.

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