# adjusting the pressure



## paul whu (Sep 25, 2014)

The pressure on my machine is 12 bar when extracting (according to the gauge). The coffee still tastes marvellous but I'd like to get as near to perfection as physically possible. The machine is a single boiler Vibiemme Domobar and I'm sure it used to run at 10 bar.

Can anyone tell me how to make the adjustment please?

Thanks in advance!


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## El carajillo (Mar 16, 2013)

Presuming it has a vibe pump, coming off the end supplying the brew head there will be a brass valve ( O P V ) probably with a plastic pipe leading off to tank (or possibly tray )

On the valve will be a slot headed screw (quite large) removing this should expose another screw head which varies the pressure on a spring and simple valve.

Remove second screw, spring and valve. Clean inside the valve, the valve seal and spring. Lightly lubricate seal and refit, screw in adjuster screw to approx original position, run machine and check pressure, adjust as necassary then fit cover screw.


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## paul whu (Sep 25, 2014)

Thanks very much. I'll have a crack at that. I will let you know how it goes


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## 7493 (May 29, 2014)

Paul, when I had it I adjusted it down to 10 bar when the blind basket was fitted, which translated to around 9 bar when brewing. I guess it may have vibrated out! If I remember correctly the unit with the screw is bottom left, looking at the machine from the front, with the covers off. Please let us know how you get on.

PS I don't remember having to remove a screw to get at the adjuster. I think it's the one you see on the unit.


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## doolallysquiff (Jul 26, 2014)

View attachment 20127


Turn the big screw with a coin - quarter of a turn to begin with. I can't remember what my Domobar was set to, but I ended up doing a half turn of the screw.


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## 7493 (May 29, 2014)

That's the one! Half a turn did it for me.


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## paul whu (Sep 25, 2014)

Hoorah!!!!! Utter success. Screw was a little awkward to get at owing to a few wires being in a stupid place. Anyway half a turn has got me extracting at 8.75bar.

I would love to be able to comment on the difference in the cup but I can't as I has just begun a new (to me) bean. I guess I need to grab an old favourite. Incidentally the espresso I have had was delicious, just don't know the impact of the corrected pressure.

Thanks for the advice, really appreciated. I hope I get the opportunity to return the compliment one way or another!!


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