Thanks so much, Brian. That's about as exhaustive an informed diagnosis as I can imagine.
Your comment about plumbing problems being permanent while electronic failures are often intermittent might be relevant. The very first time the problem occurred (hissing and steam during group head water flow), I was pulling a shot. I noticed that something was wrong with the pull — the cone on the naked portafilter was foamy, spurting, and more voluminous than normal. That's when I heard the hissing and saw the steam. During the shot, the PID showed 200°. When I lowered the group lever, however, the PID display suddenly shot up to 220°. In a panic, I turned off the machine to let it cool down. Through the subsequent times the problem occurred over the next day or so, the display never again read 220°, but that was one reason I thought the PID might have failed, as I asked in my initial post. If the problem recurs, I'll remove the case and check the controller wiring for corrosion or loose connections. I'll also try your suggestion to purge a cup or two of water from the steam boiler through the hot water tap to lower the steam boiler water temp after it refills but before reheating. If that lowers the brew water temp and stops the hiss/steam, it should indicate if the problem is plumbing related, probably through back flow from the fill valve. I appreciate your common sense statement that the high internal temp of the Brewtus is hard on electronics. Historically, I'd always turned off my old Brewtus II and more recent IV-r after making an espresso. Over the past year, I've been drinking 3-4 cappuccinos throughout the day, so I'd been leaving both boilers turned on 24/7. Whether because of profligate energy use or wear and tear from internal heat, that probably wasn't wise. At this point, I turn off the steam boiler after each use. Seems prudent. On Monday, September 6, 2021 at 10:41:48 PM UTC-5 Brian wrote: > Hey Bill, > > Glad the problem went away but heres a few thoughts to help should it > return. > > The two boilers are only connected at the fill, and the solenoid is > supposed to prevent any flow between when neither is filling. Should this > fail open it would be possible for water from the steam boiler to enter the > brew boiler. Additionally there is a copper preheating tube as part of the > brew boiler fill pathway that runs through the steam boiler. If that tube > or the fittings were to fail it is possible for water, or worse steam, to > flow into the brew boiler. Descaling is done with acids that breakdown > mineral deposits, and also break down copper and brass. The reason copper > and brass look so damn shiny after a strong acid soak is because the outer > corroded portion of the metal has been chemically stripped, exposing fresh > metal underneath. It's certainly possible with a strong enough acid, and a > long enough contact time that the copper tube that passes through the > boiler may have become weakened and failed, though I admit that seems > unlikely. > > That said I do not believe either of those is probably the cause. With a > rotary machine, and especially if it is plumbed, my intuition says that it > is pretty unlikely that the relatively low amount of pressure in the brew > boiler would be able to over come the pump pressure. Additionally any water > entering the brew boiler would assumedly mix with the relatively large > volume of water making it unlikely to get to the grouphead without blending > some. And if it was heating the temperature of the brew boiler then the > temperature controller should show that the boiler is over temp before you > send water to the brewhead. I assume if this was happening you would have > mentioned it. > > What seems far more likely to me is that the extra heat inside the case > from having both boilers on is causing the temp reading that the controller > is seeing to appear low so it overheats the water. I would check from > corrosion or loose connections to all the wires on the temperature > controller. It could also be a bad controller or a bad probe. These > electronics do not do great over the long term with how hot the inside of > the brewtus gets. Additionally plumbing problems tend to be permanent, > while electronics issues can often be intermittent. > > One thing to keep in mind, the temp display on the temp controller > actually has an offset of between 10-18 degrees F. This is because the > controller is measuring the temperature of the water at the boiler, but > what we care about when making espresso is the temperature at the > grouphead. The water by the time it reaches the grouphead tends to be about > 10-18 degrees F cooler than at the boiler. So at a setpoint of 200, the > water in the brew boiler should actually be about 210-218. Just something > to remember as you go about troubleshoting. > > Best of luck, > -Brian > > On Sunday, September 5, 2021 at 9:45:23 PM UTC-4 billherbst wrote: > >> >> UPDATE: It's now been a full day since my first troubleshooting >> experiment (turning off the steam boiler). Oddly enough, everything is >> working properly, even with the steam boiler turned on and at full >> pressure/heat (1.3 bars). No hissing or major steam through the group head >> as happened before. When I activate the pump by raising the group lever, >> there's a typical 1-2 second delay before water flows with the tiniest wisp >> of steam at first (presumably because the group head is hot), but the water >> temp is right at the 200° F PID setting and remains there for as long as >> the pump runs. Pulling shots is completely normal. I'm relieved but >> cautious. I don't know what caused the problem, nor why it's now stopped >> happening. >> >> I did find a workaround in case I need to turn off the steam boiler. Pull >> a shot, pour 6 ounces of moo juice or cashew milk into a pitcher, add some >> coconut oil, then whip/froth that concoction with a stick blender. Add it >> to my long-pull espresso shot (4 ounces), then nuke it all in the microwave >> for 30 seconds. Voilá! A nice foamy latte. A bit inelegant perhaps, but >> quite tasty. Happily, though, I'm back in business — at least for the >> moment — with normal milk steaming on the Brewtus. >> >> I'm still interested to know why/how 220° water from the steam boiler was >> coming through the group head. Should anyone here have any insights, I'm >> all ears. >> On Saturday, September 4, 2021 at 2:25:54 PM UTC-5 billherbst wrote: >> >>> First troubleshooting experiment (to try to rule out possible causes of >>> the problem): This morning I turned on the Brewtus IV-r (after a night >>> where the machine was turned off), but I did NOT switch on the steam >>> boiler. I left it turned off, so that only the brew boiler would heat. >>> >>> Interesting results. The Brewtus heated up the brew boiler and reached >>> the PID set temp of 199° F in about ten minutes. I removed the naked >>> portafilter and lifted the group lever to see what would happen. Brew water >>> streamed through the group head exactly as it should and appeared to be the >>> correct temperature (no hissing or steam). I pulled a shot, and everything >>> was fine. >>> >>> I left the machine turned on and went back an hour later to check again. >>> Still good — brew water flowing through the group head was the correct temp >>> with no hissing or steam. To the best of my ability to apply logic, this >>> implies that the problem isn’t with the PID at all, and is instead somehow >>> tied to the steam boiler and internal plumbing. >>> >>> The problem I had six months ago was caused by scale. The water in my >>> town is so hard that scale build-up had caused the solenoid-operated valve >>> (the one that's normally closed but opens when the steam boiler level >>> sensor triggers refilling) to seize in the open position. Replacing that >>> valve and de-scaling the machine fixed the problem, and I resolved to do a >>> citric acid de-scale at least once a year. >>> >>> Now it’s six months later, and I’m wondering if scale build-up has >>> caused a problem with the internal valves that control direction and flow >>> of water from each boiler. I still don’t understand why and how 220° water >>> from the steam boiler can be coming through the group head, but it is. >>> Perhaps someone here knows and can explain that to me. >>> >>> On Saturday, September 4, 2021 at 4:16:23 AM UTC-5 billherbst wrote: >>> >>>> Well, there’s more trouble with my Brewtus IV-r. Judged by gauges, >>>> lights, and valves, everything is normal and operating as it should, but >>>> when I raise the e-61 group lever to activate the brew cycle, the water >>>> that comes through is way, way too hot. Yes, a stream of water is pumped >>>> through the group head, but it’s accompanied by loud hissing and a large >>>> volume of steam. >>>> >>>> The PID is set to 199° F, but the water coming through the group head >>>> is hotter than boiling — 220-230°. >>>> >>>> Has the PID failed? Has anyone else had this problem? >>>> >>> -- 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/c0caac12-9b83-4c45-a2ce-980a8bbbb5a6n%40googlegroups.com.
