Atlas Copco Air Compressor Will Not Stay Running – Atlas Copco Air Compressor Troubleshooting

Published Categorized as Air Compressor Won't Keep Running, Atlas Copco 12 Comments on Atlas Copco Air Compressor Will Not Stay Running – Atlas Copco Air Compressor Troubleshooting

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A common problem often found on Atlas Copco air compressors is them not being able to stay running. This article will provide you will all the possible reasons as to why your Atlas Copco air compressor won’t stay running, along with existing reader questions and responses related to the issue.

To learn more about Atlas Copco air compressors, visit our Atlas Copco air compressors brand page here!

Table of Contents

Reasons Atlas Copco Air Compressor Won’t Stay Running

At times you might have to face an issue with Atlas Copco not staying running, where the power light is on, and it might seem like the air compressor is on. But the Atlas Copco air compressor will not be working and there will be no pressure in the air compressor. This is often due to the following reasons:

  • Power issue
  • Using an extension cord
  • Faulty run capacitor
  • Faulty unloader valve
  • Air leak
  • Oil leak
  • Motor overheating

First of all, you should check all the wiring. Once you have fixed the wiring issues, if there are any, and have ensured that the plug is in the wall properly, you will need to press the reset button on your air compressor and hopefully, this will solve the issue.

An air compressor may work fine on an outlet using the supplied power cord, but if plugged into an extension cord that has insufficient power, your Atlas Copco air compressor will not stay running. If you must use an extension cord, make sure suitable for this kind of application.

A faulty run capacitor that is failing during running after the start capacitor gets the compressor going is possible. If the run capacitor keeps tripping, causing the motor to shut off, you will likely need to replace the run capacitor to be able to use the air compressor as required.

Another problem could be your unloader valve not working correctly. The unloader valve is designed to relieve pressure from inside the pump after the motor has stopped. If you have a problem, it may sound like the pump is working extra hard at start-up and during the initial stages of operation before the compressor stops.

An air compressor not staying running can also stem from other issues, such as an air leak, an oil leak, or a broken part. In some cases, you might have insufficient pressurization or airflow causing the compressor to come to a halt. It’s important to check the whole air compressor system for signs of leaks.

It may even be as simple as the compressor overheating, meaning that the thermal overload is tripping and the compressor is shutting down to protect the motor, allowing it time to cool down. Visit our Air Compressor Reset Button Always Trips guide for more information!

Additional Atlas Copco Pages

Reader Questions & Responses

Atlas Copco Air Compressor Won’t Stay Running – Atlas Copco XAS 185 Troubleshooting


I have an atlas air compressor XAS 185 JD7 that starts up but once I let go of the crank position and it goes into the run position it turns off and won’t stay on.

Atlas Copco XAS 185 JD7


Atlas Xas 185 jd7 won’t stay on

It cut off right after I let the main switch go back


I was reading this and I have the same issue. so I bypassed the temp switch and it runs for about 60 seconds now then it dies. it will crank right back up and do the same thing again. thanks


Your compressor oil temperature switch is bad. Take the two wires off and put them together and the engine should start. Order another switch you do not want to run it long without it connected in case the compressor oil is getting too hot.

Atlas Copco Air Compressor Won’t Stay Running – Atlas Copco Air Compressor Overheating


I have a GX5 that keeps overheating.

I’m running a CNC machine shop, that has 5 machines in it. I run this place myself so most of the time I run one machine, and have no problems. As soon as I try to run two machines at once, the compressor has overheating issues. A couple of years ago, I had a crew of 3, and we would run 4 machines at the same time, had no issues with the compressor, so I know running 2 machines should not be overworking this compressor.

Called service a few times on this, and this is what has happened. The oil, oil filter, and oil separator have been changed. The thermostat has been changed. The intake air filter has been changed. The oil cooling radiator has been taken off and complete power washed so it’s clean as new, and also blew air through it to make sure it’s not plugged.

I checked with a temperature gun when it overheats, and it’s definitely reaching 213 degrees, so I know it’s getting hot. I don’t know what else to do with this thing. Could the pump itself have a bad bearing that’s getting everything too hot? It’s turning on about every 6-7 minutes.


Well, there are only a few things that can cause overheating, and looks like you’ve covered most of them!

So the cooler is clear and has full flow through it, is it actually getting hot though? It does sound like an oil flow issue as it’s only overheating when working hard, possibly one of the oil pipes/hoses blocked up? Try removing them all one by one and clearing them.

Does your machine have an electric fan or is it connected to the motor? If electric, is it turning?

Is the compressor close to a wall? I mean is there enough airflow getting to it or letting the hot air out properly?

You are right, if the bearings on the air end are dry or do not enough flow to them then that could be an issue.

One last thing to check, sometimes there is a little gauze filter going to the airend, in the pipe/hose, have a close look, maybe take that hose/pipe off and see if there is anything in there, if there is any kind of blockage going to the air end then it will overheat.

Please let us know your findings.


Is this a tank-mounted model with no dryer?

You’ve been draining the tank?

Is the radiator getting hot?
If not the bypass valve isn’t working.

When you say ” It’s turning on about every 6-7 minutes. ” do you mean motor starts or loading?

Has anything else changed since you became a one-man shop? Piping, etc.

How many hours on it?

And yes, it *could* be the air end, but let’s hope not.


Ok to answer some questions, yes it’s tank mounted, and no I do not have a dryer on this unit. It is near a wall but had plenty of open air around all sides of it.

I had a different repair person in yesterday on it, and believe it or not, it appears someone put the thermal couple in backward. That was the whole problem with it. He flipped it over and it’s staying about 30-50 degrees cooler. Good lord, the time I spent chasing this issue. But, glad it’s all fixed now. Thanks to everyone for helping search for the problem.


Fantastic, glad you got it fixed! I thought it sounded like an oil flow issue.

Anyway pleased it’s done now.



So this was already happening, and when whoever changed the thermostat, broke it good?

Wow. This is why history is good to know.

I trust you’re getting at least a partial refund from the company that messed it up.


Doug–yes, the whole fix was free of charge. As for the last guy who put it in wrong, well, he did other maintenance on the machine besides this, so I doubt I’ll see any refunds on that work.

The original work was done for overheating, but their remedy was to do full maintenance on it. Which they did, and seemed to remedy the overheating, but then the problem returned about 4 months later.

The only thing they didn’t do was change the separator because they didn’t have one on the truck.

So when the problem returned 4 months later, they then had a separator and swapped that out.

The problem went away again for about 2 months, then returned again.

Then they said the regulator might be bad. It’s cheap, so let’s replace it. Which they did.

The problem went away again for about 2 months, then returned again. It wasn’t until now that a different repair person came out to discover the regulator was put in backward.

If you have any questions regarding Atlas Copco air compressors not staying running, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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I have a xas 185 HD will a relay stop it from running

Yes. See attached – yours should be substantially the same.

Screenshot from 2021-06-11 23-18-21.png

Ours was doing this and it ended up being the low fuel cutoff switch on tank. On ours all the switches have to be closed(Jumper wire both plugs on switches to test) in order for it to run. If you jumper all the plugs from switches and it runs. Start by plugging the switches back in one at a time to see which one is bad.

I have a xas 185 with the John Deere engine. It seems to run fine and blow great air but it all the sudden just shuts off. It starts right back up and will run for a while and then shuts down again. It doens’t matter if there is a load on it or not. Some days it will run for hours and nothing happens and then some days it will shut down 4-5 times in an hour. Any idea? Thanks much

The fact that it starts right back up suggests the start/run switch may be flaking out. Before replacing it, take a look at the wires and connector – could be loose or corroded. After that, things get really tedious, short of replacing all the electrical, and there’s no guarantee that would fix it.

All that given this does not have an electronic controller. Maybe you could post a pic or three of it if it does.

i have the same compressor and when the top light comes on it shuts the machine off.. and blows oil out of the air lines,,, any ideas!!!

Sparse info there, but oil out the lines is ordinarily a separator problem. You probably want to check the element and the scavenger line. I daresay the element is soaked.

I’m having the same trouble with my atlas Copco 185JD7 replaced oil temp switch replaced the oil switch temperature switch and I’m still getting the same thing engine cutting off

Robert, sorry, but there a couple different problems up there, and below. You say you replaced the low oil level switch along with the temperature switch? And it cuts off exactly when? and how – like you switched it off?
No other indication/abnormality?


Did you ever figure out the problem ,I am having same issue starts right up but when I let go of switch stalls thank’s for any input

I have a xas 97 185 cfm tow behind. It starts and runs good but no pressure registers on operator’s gage and the engine will not slow down when air valves are closed, but blows out the relief valve. What do I need to do.

That gauge is direct, can you replace or test it? Otherwise, sounds like: 10. Compressor does not unload and engine keeps running at maximum speed when closing the air outlet valves; safety valve blows. a. Air leaks in regulating system. … Check and repair. b. Regulating valve (RV) incorrectly set or defective…. Adjust or repair regulating valve; see section Adjustment of the continuous regulating system c. Unloading valve (UV) or its actuating piston stuck….. Repair unloading valve assembly. You should be able to find a manual on-line: There may be one here by the time you see this. (Manuals of… Read more »