Dryer purging every 30 seconds

[bkellerm]

I have a 1997 cummins 8.3 with a holset compressor and AD-9 dryer. The dryer is purging about every 30-45 seconds. It does this whether I am parked or driving. I know I do not have any air leaks as I only lose about 5 PSI over 24 hours.

A couple of other details:
-The pressure in the tanks seem to stay steady at about 120psi. It is like the the compressor cut-in is too ealry (or could it never be cutting out?)
-I just replaced the desiccant cartridge but didnt rebuilt the purge valve.
-About 10 seconds before the dryer purges there is kind of a "soft" purge that lasts for about 1-2 seconds.

Any help or advice of what to look for would be greatly appreciated. I am hoping that it is not the unloader valve in the compressor. If it is, how hard are they to change or rebuild?

 

[Doggie Daddy]

Can you hear the compressor running all the time?

 

[guido4475]

Change the governor on your air compressor, a $14.00 part, that you can adjust your air pressure cut-off by unscrewing the black cap at the end, loosening the nut, and turning the screw to the desired pressure.Changing the dessicant on your air dryer was a good thing, it should be done once a year anyway.