Air Compressor won't shut off

[GNDxero]

Guys, I've got a probably 8 year old craftsman compressor, that has progressively taken more and more time to shut off, and the last 6 times I've ended up getting frustrated with the noise, before it ever shut off, so I'm tempted to say it just can't quite build up enough pressure. Anyone have similar compressor problems?

 

[Matt018]

There could be a leak in the compressor, Let the pressure build for a few minutes and then turn it off and see if you hear a leak.

 

[GNDxero]

Yeah i mean, there for sure is a small leak in the hose, both ends, but this is even without the hose plugged in. Also, my drain valve at the bottom used to leak, and now doesn't, because it broke off. I bought a new one to replace it, also, thinking that there might be water in the bottom because i haven't been able to drain it.

 

[Outlawmws]

What pressure is it getting to? What does the gauge say?

If you suspect leaks, use soap spray to look for them in all the joints etc.

If you suspect the hose disconnect it and see why happens.

 

[larry_g]

Without pressure readings your just guessing at what may be going on. What pressure is it building to? If your pump is worn then it may not be capable of making the pressure it once did. Some of the manufactures push the limits of the pump and set the pressure switch quite high, 135+ for a single stage. Get a bit of wear in the rings/bore and the pump will no longer make 135+psi. So if your pump is making 135+ and still not shutting off then lower the cutoff setting. If your peaking out at 100 psi then you have bigger wear problems, or other problems like leaks, slipping belt, clogged intake filter, or others.

lg
no neat sig line

 

[crewchief888]

oilless or piston type compressor?

 

[kythri]

My oilless Craftsman won't auto-shutoff either, but I believe it's a bad pressure switch that I'm too busy (lazy) to purchase and replace.

 

[GNDxero]

WOW, lots of great responses.
Um, i think it's an oil-less.
It's getting up to like 125, and i think i remember it shutting off at like 130 or 135. It pretty much just holds at 125 and doesn't got any higher. Then when i shut it off, and hose removed, no leaks.

SO, if the pump is worn, then what are we talking? $5 rebuild kit? $200 rebuild kit, or do people generally just go with a new compressor?

 

[crewchief888]

WOW, lots of great responses.
Um, i think it's an oil-less.
It's getting up to like 125, and i think i remember it shutting off at like 130 or 135. It pretty much just holds at 125 and doesn't got any higher. Then when i shut it off, and hose removed, no leaks.

SO, if the pump is worn, then what are we talking? $5 rebuild kit? $200 rebuild kit, or do people generally just go with a new compressor?

i (unfortunately) have a CM oil less as well
mine was doing the same thing, wouldnt build up to cutoff pressure.

got all the parts i needed, piston, diaphram, rod ect for under $100 shipped from sears. i'd advise getting a new cylinder ($25) as mine was scored up pretty bad after i got it apart.
it ran great for a couple years even with the badly scored bore.

 

[GNDxero]

Hrm, yeah, i was thinking they'd probably price the rebuild half what a new one costs. So i'm the type of person that would be more inclined to pick up a nice compressor than to put money into one that will still be a lame compressor. So what should I be looking for? Seems like NOT oil less. I'm happy with NOT CM.
Heavy user of - nailguns, paint sprayer, DA, grinder, impact.
I'm also inclined to find a craiglist deal on a used, commercial compressor and rebuild that. Thoughts?

 

[Outlawmws]

Depends on what you have now. If you have a large tank, and a large enough motor, you could shop for a oiled head and move on. If its a small tank/motor, you may not want to and your plan makes better sense.

Not enough data....

 

[GNDxero]

Yeah, totally hear you with the not enough data. I don't know the size of the motor or the tank off hand, but I'm picking up what you're laying down. I'll get the specs from the compressor and report back.

 

[toolmaker1]

I would buy a good oil lube compressor and keep your current tank to plumb in for extra air storage if you have the room

 

[GNDxero]

Yes...I'm liking the sound of that. I recall thinking about that in a passing moment wondering if that's possible. SO that would give me, more CFM correct?

 

[98TJ]

What is the model number of the compressor?

 

[Outlawmws]

Yes...I'm liking the sound of that. I recall thinking about that in a passing moment wondering if that's possible. SO that would give me, more CFM correct?

No, not in the generally understood sense. CFM is tied to the pumps ability to deliver, and to the recovery rate of the tank to full pressure. A pumps ability to deliver a given CFM is also tied to the pressure it is working against. (hence the practice of rating CFM at say 90 PSI and some higher PSI which will always be lower, due to the back pressure.)

What it will do is give you a larger volume to work with, before the pump starts up again and starts its recovery process, ,the larger the tank space, the larger the "buffer" but also the longer it takes to get to max/shutoff pressure.

 

[GNDxero]

Ok, snapped a few pics of relevant data.

 

[Outlawmws]

Wow, I'm surprised that the HP/Amps rating on the motor are that high. If the tank size is working for you OK, looking for a pump head is an option... Do pay attention to cost of that, vs. a new compressor...

 

[joshuaz223]

gotta love the way they rate these compressors hp. the only way that motor could see 5.5 hp would be in a surge and that would have to last less than 1/100 of a second. 15 amps of 115 single phase will provide 2 continuous hp with a highly efficient motor. for a compressor to perform like the one you have that is a realistic hp to look at. look for a low rpm pump. they will last longer and make less noise.you will pay more but it is worth every penny. i have a 5 hp low speed two stage pump on my compressor and you can stand next to it and talk while it is running and i never have had a air shortage.

 

[GNDxero]

I really like the idea of quiet, as this one is deafening. I've been planning to build a box around them and put them in the basement of the garage just to get away from the noise. I've actually got a trailer mounted generator / compressor, made by pelsue, use to be used for man holes. That compressor chugs along and is nice and quiet. hrm. maybe i should mount my tank to that one, (25 gal as well), plumb it in, and wire it up to run off of house power. I'd like to have a permanent place for the gen/compressor on the outside of the garage, but still have the ability to drive it around. So maybe I just have a plug to provide power to it, a plug to send power back when the power goes out, and an air line and plumb the garage....