Well I guess the good news is you know the cause. The bad news is that you have a leak in your steam boiler.
I have a brewtus that has a second switch to turn off the steam boiler. I guess its good because I never froth milk, but in practice I leave the steam boiler on because that line through the steam boiler helps the machine have correct brew pressure and make better shots. I fear your correct approach is going to be to take out the steam boiler and see about getting that leak fixed. In short term, you've bypassed the steam boiler on the brew path, I guess you could cap off the in/out to the brew line through the steam boiler, then at least the steam boiler couldn't leak out. I'd love to see photos of the place with the leak. I think the boilers are brass so shouldn't corrode, and mine look well constructed - not sure why there's a leak. Good luck to you! On Wednesday, July 16, 2025 at 8:20:25 PM UTC-7 Flo Kraus wrote: > Hi and thanks a lot for your responses, both Eric and Ben. They really > helped me narrow down the problem further and to find a solution > (partially). > > *To keep it short:* The issue was a small leak in the riser pipe through > the steam boiler, which caused pressure to transfer to the brew boiler. > Since there’s no additional valve between the pump and the brew boiler, the > pressure was able to push the water back. I bypassed the riser pipe through > the steam boiler, and now the brew boiler isn't emptying anymore — so > that's progress! > > However, the steam boiler is now losing water. I still got a flowback and > every 3-5 minutes the pump turns on and fills the steam boiler. > > Looks like I’ll need to open up the machine again in the next few days and > investigate further. Stay tuned. > > And now. let's answer some of your questions: > > Flows back into *which* tank? > By “return line”, what do you mean? > What model of Brewtus do you have, and is it a machine with a vibe pump or > a rotary pump? > > It's a Brewtus IV - standard Ulka pump. > [image: Screenshot 2025-07-17 043142.png] > > > The only place I can think of where the two boilers are connected is the > fill piping (i.e. where they get fresh water from the pump). That solenoid > opens/closes as needed to bypass water to one or the other, so that’s one > source of leak perhaps? If the water in the brew boiler is at higher > pressure (which I believe it is, at both rest and extraction), then I could > see the brew boiler’s water perhaps expanding and pushing backwards through > the fill solenoid to the steam boiler? > > No, it's the other way round - Steam pressure is set to 1bar and resting > pressure of brew boiler should be room pressure - when extracting it's > 9bar. So pressure was > > > Expansion valve? There is an emergency over pressure valve on top of the > steam boiler. That should never be open unless youve got a serious problem > like if the pstat is stuck open. It will whistle like a steam engine and > gorge steam. The reverse pressure relief valve on the steam boiler should > also not be leaking, like... ever. It sets and seals itself every time the > steam boiler comes up to pressure. > > No, I meant the OPV. emergency over pressure valve on top of the steam > boiler is fine. > > There is a switch to cause brew boiler fill. When brew boiler gets low the > pump will activate to fill it. How low is the brew boiler getting? Not good > if brew boiler is actually emptying. Or do you mean it takes a while for > brew water to reach group head? > > It's the other way round - there isn’t a switch for filling the brew > boiler. The solenoid valve is responsible for filling the steam boiler. > Filling the brew boiler happens solely by starting a extraction. > > I am not sure what you mean by air relief valve. The reverse pressure > relief valve? That is sealed when steam boiler is at pressure. If it leaks > it leaks steam into the enclosure, no tube to collect its output. > > Number 3 in the explode view. but I don't know the function of that valve. > The reverse pressure relief valve works just fine. > [image: Screenshot 2025-07-17 050119.png] > > > -- 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 visit https://groups.google.com/d/msgid/brewtus/0a2c5301-2062-43ba-828c-9c5cb935b163n%40googlegroups.com.
