Sullair 4509/A failure to unload

by Bob ward

Hello, my 4509/A keeps shutting down and the fault os failure to unload. Is there a simple fix for this issue?

Comments for Sullair 4509/A failure to unload

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Feb 17, 2016
Failure to load
by: Anonymous

Check ur coupler

Dec 12, 2015
Inlet/unloader valve
by: Carl

Have a look at your inlet valve or the load/unload valve solenoid, it may be stuck. You can get a service kit which should have the parts in it to fix.

In short, the compressor loads and builds pressure, the controller tells the inlet valve to stop loading via a signal to the solenoid, it then stops loading. But, if the solenoid is stuck then it wont stop loading.

Also have a check to see if the signal is actually being sent from the controller, see what voltage you are getting when loaded and see what you get when it is supposed to be unloading.

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