Can I adjust the OPV on a Bezzera Galatea Domus?

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#1: Post by Maz »

Hi all, hope you're well.

Is it possible to adjust the OPV on a Bezzera Galatea Domus (vibe pump)?

I scoured through what threads I could find and this is the closest one there was to my issue. It helped in understanding OPVs and their function, but didn't quite help me solve the issue I'm having: \

Understanding the impact of OPV settings?

Some background that might help - I've been a Breville Dual Boiler owner for about 7yrs and loved it. I recently (with a ton of luck) managed to buy a second hand Bezzera Galatea Domus for very cheap. I'm stoked as this is my first fancy machine after always drooling over ones like this in coffee shops and the interwebs. I replaced the gaskets & seals right away and it works great aside from the pressure being too high. I have to grind quite a bit finer using the same IMS basket I used on my BDB to get the same shot volume & time, though it tastes only half as good - darker and not as pleasant. I run a cooling flush before each shot and am more or less used to temperature surfing thanks to the Rancilio Silvia that I snuck into the office at work. The grinder I'm using is a Eureka Specialita and I roast my own beans, if that helps any.

I installed a flow control valve that came with a pressure gauge that's reading 12.5bar with a blind filter. I'm sure that's not as accurate a reading as a pressure gauge mounted on a PF, but it still seems high. I could use the flow valve to compensate, but I figured it might be better to lower the pressure at the OPV and fix the issue at the source.

Is this possible? And am I right in assuming that shots from this machine should be at least as good as, if not, better, than my old BDB?

Thanks all & stay safe :)

Team HB

#2: Post by JRising »

I don't know Bezzera machines, but the OPV in the parts breakdown sure looks like a typical adjustable OPV.

Because you've got the flow control on there, you might want to leave the OPV pressure a little higher than the 9 Bar to which you would set a typical HX without flow control... You've got the flow control to limit flow and effect the pressure drop across the puck, having the OPV at 10.5 (or even 12, Lelit ships the Bianca with the bypass at 12 Bar for very wide range, and the user can start with the paddle closed to avoid blowing the puck to bits.), just to have that range if you have some beans that might benefit from it.

TLDR: Yes, it looks in the parts diagram that yours is adjustable.

Maz (original poster)

#3: Post by Maz (original poster) »

Awesome, thank you!

Before installing the flow control, the shots showed signs of channeling and would thin too quickly, so the paddle has definitely helped. I'll follow your advice and be sure to keep it above 9bar if I manage to adjust it. 10.5bar sounds much more reasonable than the nearly 13 it's at now.

Thanks again