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Chicago pneumatic Road compressor

Dean Burn November 11, 2018 1 Answer

Question

Hi. I have a chicago pneumatic cps 90 Road compressor but the problem I have with it is that when I turn the out let valves off the compressor keeps on pumping and will not cut out. It will stay pumping all the ways in to the red on the pressure gauge. So as a result I have to keep the out let valves open all the time. Any help would be appreciated.

1 Answer

Expert 7 years ago

Hi Dean,

You inlet valve is staying open, so the compressor keeps pumping pressure.

This could be because of two things: the inlet valve itself, or the control air.

When the pressure rises, does the engine RPM go lower, or does it also stay high?

If the engine RPM goes down, but inlet valve stays open - the problem is with the inlet valve.

If the engine RPM stays high even at high pressure - the problem is with the control air.

The control air controls both the inlet valve and the engine RPM at the same time. It is created by the regulating valve (the one you turn to adjust the pressure). That valve might be dirty or broken -

Or there is a leak somewhere in the control air system, in which the control valve can't built up control air pressure and the inlet valve will stay open and the engine RPM stays high.

Hope this made any sense :) Please let me know what you find!

Cas

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