I had something very similar <https://groups.google.com/forum/#!topic/brewtus/i-ZG6BqrXxE>, and if you read further back you'll see comments suggesting its related to either the OPV or the pump, or both. But it is not definitive which is exactly at fault.
Personally I did the WLL's drain tube measurement to verify pump performance <https://www.youtube.com/watch?v=kEl-uNOC1P4>, and found that not enough water was being ejected when you use a blind basket. In my case, the OPV was set to high (around 12-13 bar). When it is set this high it seems to affect other function. When I dialed back the OPV the drain volume was correct again. Another thing I had was a tiny kink in the T of the drain tube from the OPV assembly, so not sure if that was related... the way it was installed there is still not a perfect line running from there, but so far the machine has been operated normally. The strange thing I observed, and I expect you *may* see as well, is that when you use the blind basket the pump WILL hold full pressure without periodically switching back to 6 bar. It is only during actual extraction that this oscillating behaviour occurs. Is this your case? The other interesting, but possible coincidence was that this jumping back and forth between 9 and 6 bar while brewing was perfectly in sync with the PID controller's activations, Basically when the element was on, it would go down to 6 bar, and when it was switched off, the pump went back to 9. I have a B III with the PID, and the dot/decimal point blinks when, as far as I can tell, the brew element is being activated. But I don't know how this would translate to a non-PID machine, since I expect a thermostat would have a considerable deadband and not exhibit this kind of pulsing power cycling for the element. On Sunday, 12 January 2020 09:38:45 UTC-5, Richard wrote: > > I have a Brewtus II that is about 12 years old. > I recently replaced the pressure stat and the o-ring in the vacuum relief > valve.. > > I am now seeing the brew pressure fluctuating when pulling a shot. > Pressure gradually goes up to 9 bar, pauses, drops to 6 bar and then back > up to 9 bar. Sometimes this happens several times while pulling a shot. > > *Is this a signal that the pump is starting to fail?* > *What are other symptoms of impending pump failure?* > > Another fact: I can't turn the screw that adjusts the pump pressure. It is > frozen. > > It may be possible that I have a loose electrical connection inside that > happened when I replaced the pressure stat. > I plan to open the Brewtus and check all the connections. > -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/brewtus/88c5a8a5-de91-4339-b723-d18204139d99%40googlegroups.com.
