Compressor Not loading

Wajid asked 1 month ago

Atlas capco screw compressor no building pressure because inlet valve not opened.  I check valve is good and solenoid works ok but problem is there is no pilot air in line . So what can be problem?

2 Answers
Cas Staff answered 3 weeks ago

Hi Wajid,

Thanks for your question. Sounds like you did the most important checks already and found the source of the problem: no control air.

(for others reading this: inlet valves are controlled by control air. The supply of control air is controlled by a solenoid valve. The solenoid valve is controlled by the control module/panel.)

You need to figure out:

  1. Is there no control air at all?
  2. Is there control air, but just not going to the inlet valve.

Let’s start with the last one: the control line/hose from the solenoid probably goes to the top of the separator vessel. It’s the ‘source’ of control air for the inlet valve.

Please disconnect it there and check if you have compressed air there. If yes, the hose is plugged with dirt.

If there is no control air at all, it generally is one of two things:

First on is that the MPV (minimum pressure valve) is leaking, all air escapes into the compressed air system (this would normally only happen if the system is pressure-less.

Secondly, there should be a small hole or bypass in the inlet valve. It allows the compressor to take in a little air, even when it is running unloaded.

This air is needed to built up the initial unload-running pressure of around 2.5 to 3.5 bar. This is needed to operate the inlet valve.

If that hole is plugged with dirt, there will be no pressure at all when the compressor runs unloaded, and it won’t be able to switch to ‘load’.

Please check these things. Let me know what you find out, love to hear of you found the problem.





Wajid answered 1 week ago

Thanks Alot sir. Yes i check inlet valve and pressure maintain valve and as well as solenoid valve all good but there is no air at all in pipe and even in seperator bottle.

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