My domobar super recently has started to overheat. What I mean is the boiler does not turn off and the steam gauge goes past max and the pressure relief goes off and the machine starts hissing like a steam train. I tried adjusting the pressurestat up and down but it did not make any difference. I tried again with the power on and got a huge spark. Thank you whoever invented RCD switches Does this mean that the pressure switch is faulty and should be replaced?

StevenO wrote:Does this mean that the pressure switch is faulty and should be replaced?

It sure sounds like it. How old it is and how often do you run it? A pressurestat can fail always on if the contacts arc enough to weld themselves together. Depending on the type of pressurestat and how close it's run to its maximum rating, that can happen after a few years.

The machine was serviced about 8 months ago (pressurestat replaced) and I make 2 to 3 cups of coffee a day.

Would u recommend a Parker or Sirai pressurestat

It's not how many cups per day that matters, it's how many times the pressurestat cycles, which it does anytime the machine is on. Eight months for a pressurestat is 2-3x less than I'd expect, even if you ran it 24/7. Since you're using 240V, the amperage switched by the pressurestat should be low (less than half that of the same wattage heating element as the US models). The Sirai pressurestats are commercial grade and should last many years, though given the light load, I would expect a Parker/MATER/CEME to be more than sufficient. It's weird that yours fried so quickly...

HB wrote: It's weird that yours fried so quickly...

...unless the machine is scaled to the point that the pressurestat is not sensing the boiler pressure.

Thanks for the help. I'll replace the pressurestat and see how it goes.