xas 85 not maintaining pressure

by graeme
(blenheim new zealand)

Atlas Copco XAS 85 air compressor

Atlas Copco XAS 85 air compressor

starts good,goes hard with good pressure but after 10 minutes or so pressure starts dropping off,,engine still maintains revs but not producing enough air,,has new separator recently

Comments for xas 85 not maintaining pressure

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Dec 08, 2015
Low pressure
by: Doug in s.d.ca

Did you change the oil?

If not, or if so, that could be your problem.

It could be your old oil is bad, or new oil is wrong type.

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XAS 85 building pressure on it's own

by Randy
( Romney , West Virginia)

Hi all ..

Building pressure with using the button to call for it.

I'm a first time owner of a XAS 85 made in 1987. With normal start up it it would start and idle until i pushed the button to make it build pressure. The machine has been working flawlessly now when i start the AC it starts building air right away and then it will blow the safety valve and continue making air with constant air blowing from the safety valve and pushing the button to call for pressure is doing nothing.

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Jan 17, 2016
Magic button
by: Bill

Randy, take some photos of the button and location on the compressor. Start a new thread here. Cross reference it to this one. I'll move the photos here to help folks help you.

Make sure the photos are NOT high resolution as the system cannot handle them.

Jan 17, 2016
Bumping this really need help
by: Randy

Maybe some more info is needed? The button that im saying goes in on its own takes physical pressure to push it in, is mechanical and not electronic in nature. That being said there has to a vacuum of sorts to pull that button in and there should not be.

I suppose i could take a short video clip of this if any one thinks it would help?

You all may think I'm losing my head or something saying buttons are going in on there own lol.

Jan 10, 2016
Sticking Button
by: Randy

No It is not sticking I have already investigated that and was easy to rule out.

What i did find out, This seems to be a cold weather issue. 35F and below and I start having issue.

Jan 09, 2016
Pressure
by: Doug in s.d.ca

Could the button be sticking? That'd be the simplest cause/fix.

Jan 08, 2016
Building pressure WITHOUT using the button
by: Randy

Title edit: I apologize my title was to read as--- Building pressure WITHOUT using the button to call for it.

Also today I went out to start it again and this time it started as normal.

About 3 to 5 seconds after starting the button that is supposed to be pushed to call for air automatically went in all by itself.

The AC build up its pressure as normal and worked correctly.

But this is a bad thing for a couple reasons. Putting a load and high rpm on the cold engine as well there could be a safety issue with it build pressure unexpected. I really need to find out what is going on. Any help suggestion will be greatly appreciated.

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