Hi folks,

I know there are a lot of threads about OPV adjustments. I've searched as many as I could find, and I didn't find anything about the internals of the valve itself.

I was adjusting the OPV on my Tea, and after quite a few quarter turns I noticed only a very small adjustment in the pressure on a blind basket (still around 10.5). I gave it another turn and the spring came out, so I put it back in how I thought it should go and the pressure hit 16.

So, I messed something up. That spring with the white cap is what I'm talking about. Can anyone tell me which way that is supposed to go? Should the spring touch the valve adjuster or should the white cap do so?

Finally, any reason why the pressure would still be so high after adjusting that much?

Thanks, and sorry if this creates duplicate questions.

An interesting read on the OPV

The pressure could stay high if the valve was not opening enough to accomodate the excess flow. A semi stuck piston or other blockage.

Also how much water flows from the group in 60s with no PF?


What pressure is registered when flushing with no PF in the group?

You all never disappoint. Thanks very much. I'll put the spring tension back in the RIGHT position (oops) which now seems so obvious after seeing the diagram.

I'll also do the flow test and report back. thanks!

Ok, I put the spring back in the way it's supposed to and things are back to semi-normal. I still can't get it below 10.5 though. Any more twists and the plunger comes out.

Also, as far as the flow test: I got 8 ounces in 30 seconds (started to run out of water, so didn't go to 60). Not sure how that maps back to your diagram though.

Final question: The tubes are sitting awfully close to the boiler, actually touching it in some cases. I don't remember this being the case. Normal?

Seems like plenty of flow. 16oz / minute is the flow at 3 bar, so there appears to be no restriction in the group.

Against a coffee cake do you get any change in the flow from the OPV return during the shot?

Can't comment on the 'tubes' being close to the boiler. Do you mean the tube leading to the brew pressure gauge?

I didn't notice any change in flow. I just pulled a shot and it ramped pretty quickly up to 10.5 bar, though there was a visible difference in the extraction and flavor of the shot compared to where it was (~12).

I also notice that I've now got a drip coming from the plunger of the OPV. I'm just a turn or so away from it coming completely out, so I assume that's why. I'll fix this, but clearly I can't get it lower than 10.5 bar for some reason against a blind or a coffee cake.

As far as tubes, I mean the silicon tubing that is attached to the return of the OPV taking it back to the tank. When I put on the back plate, it mashes the tubing against the boiler. That doesn't seem like a good idea to me, but I guess that's the way it was.

Any other ideas as to why I can't lower the pressure? I have read that Italian spec is 11 bar against a blind basket (I think), but I can't get the shot to pull below the max pressure no matter what I do.

It could be that the OPV spring is wrong. It's happened to other manufacturers. Or the gauge is off.

Re-route the tubes so they don't get mashed

I too have to guess for either something else being "stuck" or most likely the spring being too hard/stiff...

One machine I had while back would always jump up to around 12bar (!) and no chance to cut it back any bit...
At first I though my coffee-making sucked bad time... (well that too, back then )... but then my mechanical skills came forth (I work as a machinist) and I opened the thing up and started to adjust this and that (also the OPV)...
that's when I noticed that the OPV was already in it's weakest setting... there wasn't anything more to be done... so I went to my shop, selected a different, somewhat less hard spring... reassembled the unit and was easily able to adjust the pressure to a "good" one.

it's worth a try, and these tiny springs do not cost much at any good hardware store.

Thanks again everyone.

Daniel, I did end up going to the hardware store to find some other springs. I found some at the local Ace, but when I got them home they were much too strong and I found my pressure back up around 14. Nice.

So, I decided to shorten the length of the spring that was with the OBV. After a few tries I was able to get the pressure right at 9 bar on a blind basket and the shot is much, much improved.

I'm not sure why this started happening after several years, but I learned a little in the process and had some fun along the way. 12 bar was killing my shots, from my home roast to CCC Toscana. I much prefer it at the lower end.

Thanks!

Chad,

12 bar will kill most shots imho... (maybe not some el-cheapo blend from last year (hard to kill something which has already been dead for a long time))

Springs can be a bit of a "mystery"... depending on the type of material and the heat treatment done to them they can last long or not at all..
some wear our (slack, lose their "spring")... others from being worked constantly can actually "work-harden" (become almost brittle)... it's rare but I've seen it happen a few times... usually with cheap stuff.
could be lots of issues... material inconsistencies, etc.