Bezzera BZ10 boiler pressure too high!

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#1: Post by dr1310 »

Hi guys,

Looking for some advice, i have a BZ10 Bezzera coffee machine it's around 6 years old, i have recently had it serviced, but since it was serviced and the boiler solenoid was replaced it sits way too high roughly 1.7 Bar, pics attached, i am not getting a decent coffee and it feels the pressure is trying to push way too much, should this be adjusted? if so what should the pressure be set to?

Thanks :D

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#2: Post by Jeff »

The steam-boiler pressure has effectively nothing to do with extraction pressure. The extraction pressure comes from the pump. The brew circuit is separate from the steam boiler.

It may be that the higher HX temperature is resulting in hotter brew temperature if you haven't adjusted your flush routine.

On older designs, 1.2-1.5 bar is typical. You'll often see it vary during the heating cycle over 0.3-0.5 bar. A few of the newer machines have been designed for around 2 bar. Running a "classic" design significantly above its design isn't recommended, so I wouldn't crank yours up. There is probably a small adjustment screw on the top of the pressurestat. The ones I've adjusted are very sensitive (tiny fractions of a turn) and backwards to the way I usually think. Higher pressure in the steam boiler generally means faster, dryer steaming. Although there is an impact on brew temperature with an HX, I manage brew temperature with a flush routine. Using a group-head thermometer, such as the EricS, makes this more repeatable.