brewtus 2 brew pressure control failing

[Eric Christoffersen]

My Brewtus2 has a hole behind the drip tray to reach a flathead that controls the brew pressure, along with a sticker telling me to never adjust it myself. I replaced that manky broken original that was controlled with plastic flathead some years ago with what looks like a nicer one that has a metal flathead fitting.

Today the new pressure control started failing, only getting an indicated 5-6 bar. Bunch of water goes into the drip tray.

The new pressure control looks like it could be disassembled if my snapring plyers weren't broken but I'm wondering if someone can recommend a better part that will last longer?

Or do I just order a new one?

Thanks,

Eric

[Eric Christoffersen]

Got another one form wll. While waiting the brew pressure dropped to indicated 4 bar, water just pouring into drip tray.

Installed the new unit and it also brewed with lower pressure, screwed it down all the way and got 8 bar. Over the next 4 days brew pressure rose until 12+ bar. I backed the screw back and now pressure is stable at 9bar.

Wonder if this is caused by air? I sort of remember something similar when I replaced before.

Anyway, all set no.

I'd open the old one but my harbor freight snap ring pliers were destroyed in the attempt.

[herman dickens]

It sounds like you fixed it.

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[Dave B]

THAT is caused by SCALE

[Eric Christoffersen]

Hey Guys,

I got about 9 days of bliss from this new unit, now it won't maintain pressure, and problem is getting worse.

I managed to open up the old unit and it works exactly how I expected, the screw presses the top of a strong spring which presses a hexagonal plunger with a rubber pad on its end. When pressure in main line is exceeded then pad lifts to release water. The metal at the end of the plunger feels gritty, is not smooth. Not scaly though, looked pretty clean. The metal inside is rough so makes it sticky and together with tolerances the unit is a little difficult to reassemble. Could it be there's too much friction? Maybe I sand it smooth?

Some things to note:

- No water into drip tray until pressure reaches an indicated 4 bar. The thing does hold some pressure.

- The screw control does sort of control the brew pressure, if I back it way off the brew pressure doesn't exceed (indicated) 4 bar or so, if I tighten it all the way down I get 6-7 bar. If I leave it 3/4 screwed in I get 7-8 bar. Yes I get most brew pressure with spring not fully in. I get the same brew pressures when brewing coffee and with blind portafilter.

Has anyone experienced this? Doesn't seem right that two parts that look fine are both 'defective' in the same way so I'm looking for another explanation.

I have an accurate bike tire gauge - was sort of thinking to connect it to a bike pump and see if I can't read the pressure, but that'd be air not water.

Dave: You mention scale, have you experienced this issue? Do you know how scale causes this? Its been 3-4 years since I descaled so likely there are some large encrustations in the boilers. I'm just not seeing how scale is causing this.

On Saturday, March 24, 2018 at 4:10:26 PM UTC-7, Dave B wrote:

THAT is caused by SCALE

On Fri, Mar 23, 2018 at 5:28 AM, herman dickens <herman...@gmail.com> wrote:

It sounds like you fixed it.

On Fri, Mar 23, 2018 at 2:06 AM, Eric Christoffersen <zak...@gmail.com> wrote:

Got another one form wll. While waiting the brew pressure dropped to indicated 4 bar, water just pouring into drip tray.

Installed the new unit and it also brewed with lower pressure, screwed it down all the way and got 8 bar. Over the next 4 days brew pressure rose until 12+ bar. I backed the screw back and now pressure is stable at 9bar.

Wonder if this is caused by air? I sort of remember something similar when I replaced before.

Anyway, all set no.

I'd open the old one but my harbor freight snap ring pliers were destroyed in the attempt.

On Thursday, February 1, 2018 at 2:55:07 PM UTC-8, Eric Christoffersen wrote:

My Brewtus2 has a hole behind the drip tray to reach a flathead that controls the brew pressure, along with a sticker telling me to never adjust it myself. I replaced that manky broken original that was controlled with plastic flathead some years ago with what looks like a nicer one that has a metal flathead fitting.

Today the new pressure control started failing, only getting an indicated 5-6 bar. Bunch of water goes into the drip tray.

The new pressure control looks like it could be disassembled if my snapring plyers weren't broken but I'm wondering if someone can recommend a better part that will last longer?

Or do I just order a new one?

Thanks,

Eric

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[Benjamin McCafferty]

Hey Eric,

Any chance your pump is failing instead? Before I converted to rotary, I had similar symptoms each time a vibe pump failed, if memory serves. You could search (really) old threads from me when this was happening. But if I recall correctly, the pump would sometimes develop pressure, sometimes not, and it was maddening until I sorted it out. Similar to what you describe in the OPV, the sides of the piston in the vibe pump looked totally fine, but they were worn and binding up, etc. I do think the OPV should be relatively smooth, but doubt it’s the issue, especially with a new one in there. Scale could indeed cause any moving part to bind, but a new OPV has no scale on it of course. You could also have chunks of scale that have broken off and are fouling the pump intermittently. It’s pretty easy to disassemble the pump to check for this.

As to why it would develop highest pressure at the midpoint; just taking a SWAG, but I wonder if that setting is giving just the right amount of back pressure to a failing pump and letting it work most effectively?

I’d try a known good pump, if possible. You may end up down the rabbit hole, though, because you might see scale in the end of water tubing, and get a case of the “while I’m here”s...

Best and let us know,

bmc

[Jonathan Stroum]

Eric,

 

I think Ben’s suggestion has lots of merit. Sounds like everything else is working as it should. Vibe pumps are inexpensive and readily available through Amazon.

 

JPaul

[Eric Christoffersen]

Water currently diverts to the drip tray when pressure setting is overwhelmed. I had a bad pump once, no water went anywhere until it slowly dripped through the puck.

I can check the pump but its not fun to get at. I believe pump is woking great. Why would pump cause pressure release early?

Eric

[Ben McCafferty]

You make a good point, Eric, I had forgotten  you mentioned that. However, where is water coming out when it goes to the drip tray? Is it the large hole in the bottom of the group, or the small tube just behind that?

The small tube wasn’t used with a vibe pump—over pressure sent water back to the water tank and not the drip tray. So I’m wondering if maybe you have a weak spring in the brew group, if it’s coming out the bottom of the group? Hmmm...

b

Sent from my iPhone

[Eric Christoffersen]

It is not coming out of the tiny spigot, on my machine that shiney little bent tube isn’t hooked to anything. Water is coming out of the silver cylinder that’s the bottom part of the grouphead, is fed from a big copper pipe.

I’m going to sand the old pressure plunger smooth and install, see if I can tease something into working. Damn I miss my espresso, drip isn’t cutting it.

[Eric Christoffersen]

Oh! I missed the last part of your post! Spring in brew group? I’ve never had that apart, I didn’t know there was a spring in there! If there is it is probably clogged with tar and scale.

[Eric Christoffersen]

Yes! Dissembled and the seals in the lower exhaust cylinder are hard like bakealite. No scale, no tar but seals are done-ski.

While waiting for machine to cool I Found this YouTube video, Seattle coffee gear: internals of e61 grouphead featuring bill Crossland, describes leakage when seals harden the exhaust spring can’t hold brew pressure.

https://youtu.be/2jn28YTS3OQ

[Benjamin McCafferty]

Yeah, that’s a good video; I was just looking for it too. Here’s another, from WLL: https://youtu.be/5igXx83J_Iw You can see Todd’s shining face, haha.

So yes, I’m thinking that perhaps you have a combination of hardened gaskets, and maybe weakened springs, both of which could cause loss of pressure during brewing. It’s a snap to replace all of that; while you’re there, I’d do the seals on your lever too (with some food-grade silicon grease) and also look at wear on the cam (likely is fine, but since you’re going to have it out anyway).

I’d be stoked for you if this is the solution!

best,
bmc

[Benjamin McCafferty]

P.S. do the upper spring and seal also, the green one in the video you referenced. You’ll also see wear on that (even in the video).
best,
bmc

[Eric Christoffersen]

Good idea to do the top seal too.

The brew lever seal I’ve done a few times, it’s good.

Wondering if there’s silicone gaskets I could use instead of more rubber that hardens. Best thing I ever did was get a silicone brew screen seal.

[Benjamin McCafferty]

Yeah, not sure. I’ve only ever been able to source the entire kit, i.e. spring and brass bits with seals attached already. I’d check the usual suspects, i.e. WLL, Chris’, Seattle Espresso Gear, 1st Line.

best,
bmc

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[Eric Christoffersen]

Ok. I know one thing well now: Espresso satisfies something that I am not getting from drip. Same beans but no bueno.

I replaced the 3 plungers and now all is well with the world. I had to dial the opv way back so now reads a perfect and steady 9.5 bar and the shots are coming up aces.

I had quite a time sourcing the kit. Several places out of stock, one place ordered for me, then found the most important plunger was not available, would be another week.

Finally I called a place back, desperate, wanted to buy whatever kit they had for sale. He found that the exact kit I needed was at a local store 10 minutes from my house, said they had 4 in stock. I'd called that store back on the 13th of april. Went there in person and the guy said they didn't have it. Fortunately I availed on him to look more and he found it, a little baggy of precious brass plungers for $62 + tax.

Install was trivial and shots now perfect.

So, the real conclusion: if you have trouble with brew pressure, and the opv adjustment isn't working, disassemble the big hex nuts on top and bottom of group head and see how your plungers look. Mine were horrible. After an hour boiling in caffiza it was clear there was not much bushing left to seal with. Replacement is about a 2 minute job.

Thanks guys for diagnosing this, I'm back in business.