Replies

1. 
   Troy | Dec 11, 2006 02:13am | #1

   I had the same problem with my Hitachi and I finally took it to a repair person. He fixed it and left a message on my answering machine (I was not home when he called and he was not there when I picked it up) The jest of his message was that I was not draining the moisture from the compressor addaquately. I am not sure how this could be because I thought I was fairly good about this. Anyway it was repaired to the tune of about 60 bucks. My unit is about 5 years old and is not used daily. Anyway hope that helps.

   Troy

2. 
   Steve50 | Dec 11, 2006 02:41am | #2

   I had this same problem.  As soon as it shuts off at the high pressure cut off, the tank bleeds down and gets to the low pressure start.  The part you picture is the unloader.  Follow the black plastic tube back up to the tank and is should enter the side of a silver colored check valve with a hex nut on top.  What is supposed to happen when you get to the shutoff, the check valve should isolate the tank(s) and the pressure between the compressor and the check valve should bleed off through the brass colored device you pictured.  The problem is the check valve is not seating and the bleedoff is draining your tank.  You can try disassembling the valve by unscrewing the hex nut (make sure the tank is drained) and cleaning the internals but it did not work for me.  Try the following link if you cannot find the part locally.

   http://www.toolpartsdirect.com/cgi-bin/schematic.cgi/hitachi/EC12

   You probably only need to replace the internals.  I just pulled the internals out of the new valve and stuck them in the body.  Works perfect now.

   Steve

1. 
   MyTacoma | Dec 11, 2006 02:53am | #3

   Thanks for the quick replies. It sounds like there could be some inherent problem with this model. My compressor is three years old and has seen moderate use. I guess at worse it'll cost in the neighborhood of 60 bucks to get it fixed.

1. 
   highfigh | Dec 12, 2006 02:40am | #6

   The check valve can get clogged pretty easily. Basically, it's a brass housing with a spring-loaded metal disc. If there's anything hard on the lip, it won't seal. I have a Rol-Aire and it did the same thing when one of the leaves (acts like an intake or exhaust valve on a car motor's head) broke.
   "I cut this piece four times and it's still too short."

1. 
   MyTacoma | Dec 12, 2006 10:10am | #7

   I hope we're all talking about the same things. The parts catalog labels the valve as "nonreturn valve." Am I correct? I took it apart and basically found a rubber plug/washer stuck hard in the cap with a spring in it. There was some moisture in the valve, but not a lot. Some rust was found, but no gunk or anything that would have adverse effect on the valve. Got it cleaned and assembled. the rubber piece fits little looser. It runs, but the air pressure seems to go beyond my dialed p.s.i setting. I manually shut it off after 120 p.s.i.

   
3. 
   philip | Dec 11, 2006 12:13pm | #4

   Why don't you try removing that valve , take it apart and clean it- bet you that there is gunk in there and the thing is stuck....especially as you say you don't use it much.

   Philip Marcou
4. 
   RickL | Dec 11, 2006 04:07pm | #5

   Folks often confuse the real problem with unloaders. It sounds as if it's doing it's job. If air is leaking from the unloader then the check valve is letting air by. Someyhing maybe hanging up the cover. Basically a check valve is a spring and a cap. When pressure is reached the unloader releases the air between the cylinder and tank so it can restart with no load on the piston. If air is leaking past the unloader it most cerainly would be the check valve and not the unloader. I used to service compressors so this is not a random guess.