Ah yes, my machine did not have the separate switch for steam. Once turned on, does it still use the pstat to route current between steam vs brew boilers, or do the boilers heat independently and at the same time? You said “spanner” so I’m guessing you may be in a place with 220V instead of our 110V in the US. :)
best, bmc > On Feb 13, 2020, at 09:56, Rich <[email protected]> wrote: > > thanks so much for the detailed reply! As you said this is great info so i am > glad you left both parts up. I obviously need to work on my spanner technique > as I havent seen any others have this issue, its actually quite hard to find > the bit of pipe required. As the machine has 2 switches, one for on and the > other for steam I presumed that on would still heat the brew boiler. I think > following your reply it is safer if I just wait for the brass pipe! > > thanks > > Richard > > On Thursday, February 13, 2020 at 5:25:47 PM UTC, bmacpiper wrote: > Well crap—I somehow read “OPV” in your question, instead of "p-stat". So I > wrote up this whole response before realizing that. I’m going to go ahead and > leave it, since the discussion might be helpful to someone else down the > road. But your basic questions are also answered later in the email. I’m > assuming you have a failed p-stat, which means it’s not a big deal if you > damage the old one on the way out. > > Best and talk soon, > bmc > > ----------------------- > > > Hi again Richard, > > A couple of things you’re saying don’t add up, so I want to clarify. In > fairness, I have a B2, so things may have changed. > > On my machine, the OPV (over pressure valve) is not a plastic part. The > p-stat (pressure stat) is a plastic part, however. > > Forgive me if I’m telling you things you already know, but here’s how it > sorts out: > > —The OPV is located behind the drip tray, on the right as you face the > machine, and may have a sticker over its access hole that says “do not > adjust” or similar. The adjustment screw is a large slotted screw, and is > used to adjust the maximum pressure to the brew boiler when pulling a shot or > backflushing. When that pressure is reached, water is shunted back to the > water tank (pour over machines) or into the drip tray (plumbed machines). > Note that this is not a safety mechanism; it’s used only to set brew pressure > to 9 bar or whatever. On top of the brew boiler is an over pressure device > that protects the pressure vessel from exploding, in case something goes > wrong with the OPV and/or logic controller. If this activates, it will sound > like a freight train coming through (loud hiss) and there will be > condensation all over the inside of the machine. A good time to unplug, dry > it all out, and figure out what the hell went wrong. > > —The p-stat is inside the machine, sitting atop a copper tube, and is > typically a black plastic device with 3 wires attached. This is how you > adjust the pressure to the steam boiler (I set this to about 1.45 bar). Power > goes to the steam boiler, and when 1.45 bar is reached, the p-stat is > switched to allow power to the brew boiler instead. When you hear “steam > boiler has priority”, this is the part that controls it. Since it is a direct > open connection into the steam boiler, the threaded interface between the > copper tube and the plastic p-stat must be able to seal against 1.45 bar or > more, and thus will not use grease, etc. to lube the threads. > > —In the case of both the p-stat and the OPV (and all other threaded > connections that have to be sealed), Expobar uses a food-grade sealant on the > threads. It is very thin, and dries almost instantly if the parts are hot. If > you use it to re-assemble things, you have to work very quickly, as you > usually only have a few seconds to get things tight and oriented correctly. > This sealant is very strong, and when removing parts that are sealed with it, > it definitely feels like you’re going to strip threads. I’ve spent many hours > of my life with a wrench in hand, and breaking this sealant loose always > makes me nervous, but I have also never stripped any threads on the machine > due to the sealant. I will say that it is exceptionally important to use good > technique. The best is if you have two open-end wrenches, one for each side > of the joint, that are both very well fitted to the nuts. Try to have them > aligned so that they are as close to each other as possible, and then offset > by maybe 15 degrees, and just squeeze them together to break the > part/nut/etc. loose. If you try to have one in each hand, you will inevitably > smear the corners of the nut/part and then have a tough job ahead. If you > only use a wrench on one side of the joint, you will almost certainly twist > the soft copper pipe and crimp it shut, beyond repair. > > Be sure to use a brush (brass, for example) to gently clean all the old > sealant off the threads. It will seem almost fragile and tends to flake out > quite easily. I have had success using the sealant from Expobar/WLL, but have > also used yellow teflon tape on many parts (heating elements, p-stat, OPV) > with no leaks. It’s not what Expobar calls for but does work, and much easier > disassembly in the future as needed. > > —As to your question on whether the brew boiler can be used without a p-stat, > the answer is “sort of”. Since the steam boiler has priority, you would have > to jumper power to the brew boiler if you’re not letting the steam boiler > come up to temperature. One workaround when the p-stat sticks (and never lets > the brew boiler heat) is to reverse the power out wires on the p-stat that go > to steam and brew. This basically gives the brew boiler priority, and since > the steam boiler never heats and hits 1.45 bar, power never switches over to > it. The obvious problem with this scenario is that the brew boiler gets power > continuously, until its over-temp sensor on top activates and cuts power to > it. You may have the over pressure device on top activate before that > over-temp sensor activates; I just can’t recall. If memory serves, the logic > board (giemme and/or PID) will also be monitoring temp in the brew boiler and > only sending bursts of power if the boiler is not up to set point yet, so > that’s further protection. Either way it’s outside of design specs, and not > something I’d do as a permanent fix. > > OK, hope this helps and talk soon. > b > >> On Feb 13, 2020, at 01:30, Rich <richa...@ <>gmail.com <http://gmail.com/>> >> wrote: >> >> Hi All, >> >> apologies for a spate of questions, again I have had a search but cannot >> find anything. Has anyone else had the issue of the PStat getting physically >> stuck in the brass fittings? I cant remove it so have had to buy a new >> pressure pipe which isnt in stock until the end of the month from a company >> in France (open to suggestions for UK suppliers?). Do people use grease or >> any kind of lubricant to make sure these don't get stuck in the fittings, it >> seems a tight fit and quite easy to shred the plastic? My other question is >> whether I can use the brew boiler without a PStat, I guess I can and that >> its only for the steam boiler but I wanted to check in case I missed >> something! >> >> Thanks again >> >> Richard >> >> -- >> 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 bre...@ <>googlegroups.com <http://googlegroups.com/>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/brewtus/468d7892-12c5-43ad-8506-520fb5d8fdfe%40googlegroups.com >> >> <https://groups.google.com/d/msgid/brewtus/468d7892-12c5-43ad-8506-520fb5d8fdfe%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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/brewtus/7c477aec-94ab-4ae6-92f7-d386eaa2049b%40googlegroups.com > > <https://groups.google.com/d/msgid/brewtus/7c477aec-94ab-4ae6-92f7-d386eaa2049b%40googlegroups.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "Brewtus" group. 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