Air compressor squealing and slow to start

YotaOnRocks

YotaOnRocks

Well-Known Member
Joined
Jul 17, 2007
Location
Madison
Have a IR 60 gal compressor about 10 years old. I was in the shop last night and heard the compressor kick on(it's outside in a shed so sound is very muffled). It sounded like the belt was squealing and the motor sounded like to was running slow.

Belt only made noise for a sec or two and the compressor picked up to normal speed after about 10 secs. It kicked on one more time later and did the same thing.

It was raining so I decided not to investigate it last night. Figured I see if anyone else had experienced a similar issue and could point me in the right direction to start diagnosing the problem. TIA
 
Sounds to me like its time for a new belt. Or at least adjust the tension on it.
 
Probably time for a new belt, but I don't think thats related to the problem. You can probably assume that the compressor head is working fine if it's good after a short amount of time. I'd lean toward the motor start cap as being the first suspect.
 
Could also be the check valve or head pressure relief. If the head is still under pressure when it tries to start, it might manage eventually, but will drag the belt as it tries to overcome the initial resistance.
 
Have the same compressor and had to tighten the belts a year or so ago when it started doing the same thing. Went ahead and serviced it while i was in there. No issues since.
 
Ok. Ive got some oil and a new filter for it in the shop. I'll start with changing those and checking the belt tension.

@shawn how do I check to see if head is under pressure. I know it use to blow air off a couple seconds after it shut down but I can't hear it since putting it outside.
 
YotaOnRocks said:
I know it use to blow air off a couple seconds after it shut down but I can't hear it since putting it outside.
Click to expand...

Make it cycle and listen for it to blow off. You could always leave something open in the shop (blow gun, etc), then go outside and flip the pressure switch off. The pressure switch has the blowoff valve inside of it, so it should open when the compressor stops pumping.

But my bet is probably loose/stretched belt.
 
Do I just replace the pressure switch if it isn't blowing off or is it a serviceable part?
 
My money is on the belt being loose. I have one of those same units from tractor supply. It was doing the same thing. I thought something might be wrong with the unloader so I had the air compressor guy check it out when he was servicing my big units. He tightened the belt. I felt like an idiot :lol:
 
In my shop in Boone, it would do this when there was lots of rain/moisture outside and really cold. Tightening belt helped but spraying PB blaster all inside the motor windings solved that pretty quick lol, I do this once every several months when I change compressor oil and been sounding/starting super fast and quieter ever since
 
I had to change the check valve in mine a month or two ago. If it's still hissing after it shuts off, that's pretty much a dead giveaway. Mine was bad enough that it wouldn't have the ass to start spinning the compressor and the motor would bind up and trip the breaker. I went ahead and changed the oil and added a valve and drain line while I was working on it.
 
Loose belt was the culprit. Tightened it up and while I was in there I changed the oil and air filter. Purrs like a kitten now. Thanks for the advice fellas.
 
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