Hi all,

After I rebuilt my Anita's OPV last year, I have a strange problem. I prefer to keep it at 9 BAR, but over the course of a few days, it keeps creeping up to right around 10 BAR. Thought maybe it was tension from the hose, so I disconnected it and made sure there was no twist in it when I reconnected it, but no help.

When I rebuilt it, I simply replaced the seat. Should I have replaced the o-ring too? Could that be the problem?

Mike

This may or may not be the same issue as with your machine, but I found that my Alexia OPV starts to creep up once in a while, so the last time i adjusted it, i used a extra sharp sharpie pen to mark the position on the bolt, and to my surprise, the next time my Pressure crept up from 9 to 9.5 bars, I removed the back to readjust it only to find that the OPV bolt had not moved at all...

So I believe that, at least with my machine, that the OPV pressure change might be related to some sort of "break in", meaning maybe some of the poly hoses were stretching out a little (from the internal pressure) with my 1st year of use...sounds kinda far fetched, but its all i got!

Actually this is a good point, the one time I descaled my alexia, the OPV pressure was all over the place for the first 5-7 shots (the pressure gauge was almost "spongy" as the shots would pull - meaning the pressure would creep up real slow all the way to the 9 range, instead of ramping up slowly to 3 bars and then jumping up to 9 bars quickly)...but then my machine finally "settled in". I'm guessing it could have to do with loose scale particles left in the tubing...

Randy G. wrote:If it works with a piston and spring I would have thought that the pressure would creep down as the screw loosened. I would disassemble it again and check that there is nothing that could be jamming the piston (scale, bits of metal, etc.) and check the piston and the bore for scoring. The adjustment screw should be held well by the O-ring. After reassembly and adjustment, mark the location of the screw with some paint or whiteout to check to see if it is actually moving. Think about replacing the spring if it happens again after that, and the O-ring at the same time... might as well. .

I had the same problem a few weeks ago. I wrapped the OPV thread with some teflon tape (leaving the gasket uncovered) and it hasn't crept since...

When I first adjusted the OPV on my anita, I marked it with a sharpie, per suggestions here. I went from 10BAR, to 9BAR, and over the course of about a month, it had crept back to ten. When I opened her up, the OPV hadn't moved at all. So, I adjusted it back to down to 9BAR, and left the cover off for a couple days.

It never drifted again.

Sort-of recently, I went down to 8BAR, and Ive not had any drift what so ever.

So, maybe your valve has "broken in". Try adjusting it again, and see what happens.

I think that my problem is that my OPV is good and broken in. I disassembled it a while back to descale again and my O ring is just about shot. I cleaned and lubed it and it's been better since, but I need to replace that O ring on my next parts order.

Mike