Help with air compressor issue
 

I have a 5HP 60 Gallon craftsman air compressor. The issue is that when I use it the tools lose power very quickly. If I try to use a cut off wheel it will work fine for a minute and then slow way down where it is totally ineffective. If I wait a minute and then start again it will be fine and then back to very low power.
Anyone have any ideas with what might be the issue
Thanks

Is the compressor running and you're losing air pressure or not building/maintaining pressure while using the tool?

The compressor will run when the pressure drops as it is supposed to. But not necessarily when I am using the tools unless it drops below the set point

Wait! Have you drained the water out of your tank lately? After reading your OP it looks like you're saying the pressure drops off and if you stop for a bit the cutoff wheel will work fine again. I think that can be caused by excessive moisture in the airlines.

Had to delete that previous reply.

Cut off wheels can suck up a lot of air. Many if not most home compressors can't keep up with that demand.

I will check for that thanks

Not just the cut off wheel though even if I use the impact gun , after removing 2 lugs I will have to wait a minute for enough power to get off another 2. It is a fairly large compressor 5HP 60 Gallon 240 volt so not your average small home unit

Something is not right. What is the pressure in the tank when filled?

Outlet regulator is max open?

What size of air hose and how long? Any "issues" between the tank and tool?
Good luck!

Sounds like either your hose is too small or you have a problem with your pressure regulator.

What is the shut-off pressure and what is the re-start pressure?

Do you have a filter regulator near the compressor? It is possibly clogged or too small of a filter regulator, have you oiled the tools lately?

Thanks for the replies
using a 3/8 hose 50 feet long
120 PSI is shut of pressure not sure of start pressure
Model is Craftsman 919-165600

Get a 1/2"....25' if it will reach.

Yer welcome :)

You may want to check the compressor tank outlet fitting to see if rust / scale has built up restricting air flow through. It happens.

Thanks guys. I will check everything mentioned

A 3/8" hose would not suffice for my Powernailer to drive nails through 3/4" Hickory flooring...

You've been hosed ;)

What pressure are you running the cutoff tool at?
Per the manual that compressor puts out

Approximate Cut-in Pressure 100
Approximate Cut-out Pressure 130
SCFM @ 40 psig 14.2
SCFM @ 90 psig 9.9

Most cut off tools need 11 - 14cfm.

Oilless compressors don't put out much air.

An impact wrench just needs 90 psi, not constant at the tool. Two lugnuts and done.....NOPE ;)

Charge up the tank. Stand beside the tank gauge and run the tool until it stalls/stops, then observe the pressure drop on the tank.

When you say you wait a minute then the tool works again, is the compressor motor running in the interim? If not then you likely have a supply /pressure drop (in the hose) issue.

It would be helpful to temporarily put an air pressure gauge at the tool.

The tool does not stop just loses power and no the compressor does not kick in at that point. I will try some of the recommendations Thanks

That's your best answer there.
Do some basic diagnostics. Are there any valves or devices between the tank and the tool that could be cause a flow problem (it sounds like a flow problem to me). What is the condition of the hose (kinks, collapsed places, car parked on the hose, leaks, etc). Eliminate every variable - meaning valves, hoses, devices - you can, one at a time, working your way back to the tank, to see if there is a difference.

Change out the basics first:
The cheap fitting ends have a ball valve in them which may be stuck.
(Probably not though)

The compressor not kicking with low pressure probably means a bad regulator.
(or just the setting)

The crazy me would suggest bleeding down the tank and spraying some carb cleaner into the intake and running it through.
Follow that soon after with some cleaner/lube like Marvelous Mystery Oil.
Follow that with pure gear oil or compressor oil something.

The system will be contaminated with oil and can't be used for spray painting anytime soon.

One other thing on moisture in the system. If you're using a hose reel, extend the air house out all the way, put a blow valve on the end and run the air to make sure you have any moisture out of the lines. Springtime when we're going through warm/cold/warm cycles can cause condensation in the airlines that gets trapped. As it builds up it comes out in slugs that will make an air tool bog and lose power.

Is your shop heated all the time or at all?

Look at your quick connects. Switch to a highflow one like a Milton V. Quick connects are very restrictive.

I actually do use the Milton ones. I tried the HF ones and they leaked and worked like crap.
Update on progress I went to drain the tank and the valve is broken so I am waiting for a new valve to arrive so at a standstill until it arrives.
Thanks for all of the replies and suggestions I will update my findings when the new vave arrives and I do the rest of the checks suggested

Alternatively....for the layman

When I burp my impact wrench I can hear my 50' rubber hose filling back up because it "deflates". I hear the air passing through the regulator into the hose as the hose equalizes with the tank.

It takes about a second to refill. Yours should be about the same.

I suspect the compressor is about 20+ years old based on the model # search. Also oiless? I've never had one last that long.

That would indicate that you've been emptying the condensation from your tank far too frequently! :D