AD9 dryer purging every 2 minutes

You didn’t put a new governor on when you replaced the drier ?

 

It’s possible the governor is bad but it’s funny that the governor worked ok for three weeks then started acting up again there cheap and easy to replace I would try that

 

Yes, replace governor (#3 on troubleshooting list) as Last Call suggests as that should have been done when you replaced the dryer. If that does not solve your problem then check for leaks as that is the #1 cause. See pg 20 of attachment for troubleshooting.

 

This last summer I guess due to the 2 months we had above 100 degrees the purge valve on an AD-9 on one of my trucks started causing the dryer to purge every minute or two and sometimes just stick open for a few seconds or more. Before I was able to gather one up to replace it would sometimes stick open at first purge and i’d have to turn the bolt in the center of the valve to get it to stop. It would sometimes go a day or two like it was fixed and then act up again. It would purge like you are describing at full psi in the system without the compressor even needing to be pumping.

 

Does the compressor cut out at the same time the dryer purges? If not maybe unbolt the governor from the compressor or unhook the line from the governor to the compressor cut out port. There should be air coming out to open the unloader valve in the compressor.
If you have that is the compressor still pumping air out the discharge port when those parts are reconnected?
If so maybe get a cheap air pressure gauge, 1/4" plastic tubing and some fittings. What is the air pressure in the wet tank when this is going on?
If that stays above cut in pressure tee it in at the governor on the line from the wet tank. Is that pressure is consistent above cut in? Tee into the dryer control line and check that.
I have never seen a Bendix do this but several Wabco's. The unloader valve in the head would mess up and the compressor would never totally stop building air. Then the dryer would purge often. Also one with a collapsed braided air line to the dryer on an older KW with a Bendix compressor. It did some funny stuff that would come and go.