I am using my Shoebox for the first time tonight and have a couple questions. First though, it rocks. It fills my Ninja 45/45 in less than 4 hours. Noisier than I thought it would be (definitely not a sewing machine) but considering how awesome it is, I'm cool with that.

I am having trouble with the vent/relief valve. If I fill over 4k, then disconnect the 85psi line, and try to vent it to release the tank, it just keeps venting. It's as if it doesn't develop enough pressure differential to close the tank's fill nipple check valve. If I let it vent down to 3k, then close it and try again, I can get it to vent correctly. It seems like if it seals at 3k it should seal even better at 4.5k, but I'm not sure what is going on.


Is it possible that it vents better at one point in the piston cycle than another? I tired running it for a second here and there when it wouldn't vent right, but had the cover on, so I'm not sure if it stopped in different places or what.