Hitachi - EC12

[JVC]

With next to no hrs. on this machine the non return valve caused the machine to go in for repairs. The same problem has returned soon after the repair. The repair shop was listed as a qualified Hatichi repair outlet. This defect renders the machine useless.

[DOW62]

I have read all the posts and it got me thinking, my Hitachy EC 12 also was doing the same thing as going to the top of the pressure limit shut off and then start draining air and then when it tried to start it just hummed. Well with fine grit sand paper I fixed mine and it runs great now.
First make sure there is no pressure and it is unplugged. (1)Now take the top nut off of the Non-return valve, it is the one on the tank connected to the black tubing.
(2) There will be a black Rubber #15 on the picture above and a spring inside the nut. remove the rubber without stretching the spring.
(3) Now this is where the sandpaper comes in, place some very fine sand paper on a flat surface, I used 240 grit, very softly roll the sides on the sandpaper and remove some of the sides to make the rubber smaller in size. Keep checking it by putting it back in the nut on top of the spring and see if it moves in and out freely. When I pulled mine out it was as if the rubber #15 was too tight. When I was happy that it went in and out freely I put it back in and it worked great. Hope this helped it did for me.

[Texomajoe]

I think the little italian who assembled the switch, put the #15 rubber part in upside down. After I removed the non-return valve top, mine was sticking also, but when you examine how the #15 should fit on the tube seat, turning it over stopped all of my problems without having to sand it. The machine works perfectly now.

[nursejamesrn]

Thanks for the fix, it worked great