Low brewing pressure on VBM Domobar Inox


New member
Hi there, I bought a defect VBM Domobar to repair and I need help figuring the issue out:
So, the machine brewing pressure doesn't get above 5 bar. I tried to adjust the OPV next to the ulke pump, but even when it is tightened all the way, it still reaches maximum 5 bar.
I'm wondering what could be the issue:
1) Calcified OPV?
2) Damaged OPV?
3) Worn out pump?

would love to hear some hints.


Well-known member
Aug 15, 2005
Central North Carolina
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If that was in front of me I'd replace the pump with an equivalent and rebuild the OPV. Over time pumps can weaken a bit (as you likely know) as well as the parts in the OPV becoming weaker (spring), clogged plunger, damaged seal on the plunger in some use cases, etc. If during disassembly you notice any sort of mineral buildup, then a descale afterwards would help flush things out and possibly restore even better flow.

Will also add that there's always the possibility that the pressure gauge or line feeding it might be out of calibration, clogged, etc. as well, if it's machine mounted that is.
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