Air Compressor Model GA 250 of Atlas Copco - check valve needed?

Do we need to install a non return valve on the outlet from the compressor?


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I won't argue with whatever Atlas Copco tells you to do, but I see no value whatsoever in having a non-return or check valve on the discharge of any compressor.

Where a downstream process might generate a back pressure spike, that should normally be handled by the pressure regulator that you have in the line to the application. A typical general purpose air regulator relieves downstream air to atmosphere if the downstream pressure becomes higher than the set point.

Cheers,

Bill

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Yammering noise when unloaded Atlas-Copco GA122 (30hp)

by GreyBear
(Seattle. WA)

Have an Atlas-Copco GA122 (30hp). Builds pressure just fine, and unloads at the correct set value. When it hits the unload setting (116psi) and starts dropping down to the load (112psi) setting, it "yammers" very loudly as it loads back up to the unload value - back and forth cycle, consistently - any thoughts?
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Way back when, when cars had distributors and points, you could get point chatter when they didn't sit properly (worn). Sounds to me like you have something like this going on in your pressure switch.

After you cut off the power and dump the air, pull the cover off the switch and have a look at the points (where they connect when the switch pulls in). If they are worn or burnt, you need a new switch.

Cheers,

Bill

Comments for Yammering noise when unloaded Atlas-Copco GA122 (30hp)

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Mar 17, 2011
Yammering Rotary Screw
by: Anonymous

good evening Greybear. By the looks of your setpoints (116PSI unload and 112PSI Load) you are 'rapid cycling' the compressor, the minimum between setpoints is 10PSI, you are putting undue stress on the inlet valve opening and closing and it may be causing (pardon my language) a 'farting' sound when it loads. Get a service done - change air, oil, and air/oil filters to rid the unit of any undue pressure differential, adjust your setpoints. From there, check the sizing of your storage, when running a rotary screw compressor in 'load/unload' the larger sized tank the better.

As for the yammering noise, my best guess is that the you have a 'cavitating' airend when the unit unloads - this is air sneaking past the inlet valve or past the shaft seal causing a pressure difference in the airend when there is no load on the unit.

Hope this helps

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GA75-125 stopping on Element overheat

by Charlie Hart
(Lone Star, Texas,USA)

Stopping on Element overheat. Replaced the thermostatic valve two weeks ago. It has run fine until this morning it is stopping on Element Overtemp again. Removed the thermostatic valve and heated it. It just moves about a 1/4 in. Any idea why we are losing these thermostatic valves ?

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Atlas Copco has oil coming out of air lines

by Will McMillon
(Pampa Texas USA)

Compressor has oil coming out of air lines and cuts out soon after start up

It's shooting a good amount of oil out of air line

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Oct 29, 2013
Atlas Copco
by: Doug in s.d.ca

Has many types of air compressors and systems.

Can you narrow down what you have? Maybe a model number or picture?

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