Anybody has any idea what can make the pressure go up overnight?

From the normal 7,5, its now over 12 BAR.

I didn't changed anything. Just added some beans last week.

I cleaned the machine, but it had no effect. I also tried less then 7 grams, and very light tamping. But the effect is minimal (still over 10).

Any clue?

Running a Rocket R58 with a Compak F8 OD


I checked the pressure:

  • without porto-filter its 7 BAR
  • with the blind filter its 11 BAR

I checked the blind pressure with a friend (also a R58), thats 7.5 BAR.

  • Could you mention the machine type, please?
    – MTSan
    Aug 17 '17 at 6:35
  • Added, I wanted to added via tags. But not enough rep. :(
    – Roger
    Aug 17 '17 at 6:42

As the machine is cleaned thoroughly, we can eliminate any kind of blockage. Then, a very probable reason for this is the thermostat. If it starts malfunctioning overnight (it is possible as they are electronic controllers with a thermocouple attached), then the machine may overheat your boiler. This ends up over-pressure. If possible, compare the temperature with normal temperature first.

  • Do you mean to just have some water running (without porto-filter) and measure its temperature? I'm not sure what you mean by "normal" temperature. There is a digital readout: says 104 Celsius
    – Roger
    Aug 17 '17 at 17:01
  • I mean the boiler tank temperature. 104 °C seems pretty normal though.
    – MTSan
    Aug 17 '17 at 17:59
  • Yeah, doesn't seem to be that hot. Yet, with the blind filter, 11 BAR? Anything wrong with the pump? I loosened the screw, needed to take it a few turns back. Now its back to 8 BAR. Still puzzles me, why it went up (that much).
    – Roger
    Aug 17 '17 at 18:02
  • @Roger Pump controller circuit? This is a semi-electronic machine, I assume. (I don't have one.) Probably, to control the boiler pressure during brewing, it has a PID controlled pump. PID controller may be somehow broken? You may not notice this if normal pressure of boiler is normally around 7,5 bar. When, you insert blind filter, controller commands the pump to pump more than normal? (These are just blind troubleshooting, you know.)
    – MTSan
    Aug 18 '17 at 9:03
  • It's a DB PID controlled machine. Indeed when the blind is in, the pressure shoots-up. Unfortunately the store I bought is closed for holidays. I'm pretty sure its some defect. Machine is maybe 3 yr. old. So a normal wear-and-tear is unlikely (doing 4-6 shots a day).
    – Roger
    Aug 19 '17 at 7:01

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