I had my first pstat rot on my b2. the plastic was impossibly fragile and crisped into dust when i tried to remove it. I had to use a pick to clean the plastic out of the brass threads.
I use teflon tape when reinstalling. I have some good flare nut wrenches i use whenever possible. Not sure what you mean about it being stuck. > > On Feb 13, 2020, at 09:56, Rich <[email protected] <javascript:>> 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 <[email protected]> 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 [email protected]. >> 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] <javascript:>. > 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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