Hi Flo—(and deleting the DMT hacked email): A couple of questions. You stated: >> Hot water/steam flows back into the tank via the return line >> 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?
As to resting pressure of the brew boiler, I don’t know. Mine (Brewtus 2, vibe, modified to rotary/PID) always showed a resting pressure of maybe 3-4 bar, and then I set to 9 bar for extraction. Steam pressure can be adjusted also, and I usually run about 1.45 bar. Factory setting is closer to 1 bar. On the steam boiler, the vacuum breaker opens when the boiler cools. It closes when the boiler heats. (Aside—all that fails in this part is the o-ring—I have 100 of them if you’d ever like a replacement—had to order 100 minimum). The pressure relief valve opens at significantly above 9 bar, and is usually factory preset (though I have opened these and adjusted them). Only once ever have I had that one open due to overheating, it should not open normally. The OPV, as you’ve said, can be adjusted for extraction pressure level, usually around 9 bar. 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? The only other place I can think of there being an interface is the brew boiler line through the steam boiler for preheat, as you’ve mentioned. Could that line have a pinhole leak, allowing water to slowly bleed into the steam boiler? Your symptom of “takes a long time for water to reach the group head” makes sense—if water is bleeding off the brew boiler (emptying it), when you pull the lever, the boiler fills before pushing through the group. Hmmm…not sure I helped any, but perhaps some new ideas to consider. Curious to know what you eventually find! b >> Hello everyone, >> >> After an intense troubleshooting session with my Brewtus (dual boiler), I’ve >> reached the end of my knowledge — and I especially can’t explain the >> behavior from a physics standpoint. So I’m relying on your help. Maybe >> someone has an idea or can explain something to me. >> >> to put it briefly, the questions in general: >> - Shouldn't the brew and steam boilers be separated in terms of pressure? Or >> are they actually "connected" somewhere? >> - Could someone check for me if the preassure of the brew boiler is at about >> the same as the steam boiler (1bar). >> - Should the expansion valve and the air relief valve remain sealed when >> there is a pressure of 1 bar in the return line? >> >> >> >> Problem: >> >> Hot water/steam flows back into the tank via the return line >> >> After a few hours, the brew boiler gradually empties — water gets refilled >> during extraction and it takes some time untill water reaches the group head >> >> This issue has been ongoing for about a year. I initially suspected a leaky >> valve due to scale build-up. So I descaled and also disassembled and cleaned >> the solenoid valve, expansion valve, and air relief valve. >> Today I replaced the parker solenoid valve but this doesn't stop the >> backflow. >> >> >> Observations: >> >> The issue only occurs when the steam boiler is turned on → Only brew boiler >> heated: no backflow >> >> Pressure from the steam boiler transfers to the brew boiler → Steam boiler >> heats to 1 bar, shortly after the brew boiler also shows 1 bar >> >> Note: the brew boiler is filled via a pipe that passes through the steam >> boiler >> >> Question: Shouldn't the brew and steam boilers be separated in terms of >> pressure? Or are they actually "connected" via that line? >> >> Steam seems to push back from the brew boiler (filled from above) → The >> steam boiler (filled from below) doesn’t empty >> >> Steam escapes via the expansion valve → OPV is set to 10 bar, at just 1 bar >> pressure it should normally remain closed >> >> Question: Or is that only true for water pressure and not for steam pressure? >> >> Steam also escapes through the air relief valve toward the tank → Return >> line to the tank gets hot, condensation drips through the vacuum hose >> >> >> Possible causes (only if the valves should be closed at 1 bar): >> >> Expansion valve (Expobar 30400055) leaking or seal surface damaged >> >> The OPV is only supposed to open above 9 bar during extraction — which it >> does >> >> If it’s venting already at 1 bar steam, then it’s leaking (backflow possible >> via steam pressure) >> >> Vacuum valve leaking >> >> The vacuum valve (Expobar 65000215) is supposed to open during heating, then >> close?! >> >> If it doesn’t close, steam/water escapes continuously → backflow into tank >> >> >> Thanks in advance for all your answers! 😊 > > > -- > 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] > <mailto:[email protected]>. > To view this discussion visit > https://groups.google.com/d/msgid/brewtus/418fc2c5-103f-49c0-9f4e-bbfe02e06f09n%40googlegroups.com > > <https://groups.google.com/d/msgid/brewtus/418fc2c5-103f-49c0-9f4e-bbfe02e06f09n%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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/38551D96-4D7D-4CCE-8A13-A0F218224390%40me.com.
