# ACS Minima Steam boiler leaking



## mctrials23 (May 8, 2017)

So I only noticed this when the paint on the table the machine sits on started to crack from the leaking water. I assume it got under the paint under the machine and then ran along under the paint causing a crack that wasn't hidden by the machine.

Upon opening up the machine I was greeted with a fair bit of rust around various bits.

I have no idea quite which area the water is actually leaking from as a few connections go into the bottom of the steam boiler.

I was hoping one of you guys might be able to give me some advice. I assume I am going to have to disconnect the entire steam boiler to do anything as a bare minimum.


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## coffeechap (Apr 5, 2012)

that doesn't look good, let's hope some of the other minima users can help, or ACS . Hope you get parts to fix it soon. Is this a beta machine?


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## Rob1 (Apr 9, 2015)

Did you check for leaks when it arrived? Just to give any idea of when it started. In one of the pictures it looks like the part from the element is wet. Have you turned it on with the cover off as you should be able to see the leak by doing that?

In one of the pictures the insulation looks wet so it could be leaking from the top and dribbling all the way down the sides through the insulation to the bottom...

What kind of water are you using? Looks to be a lot of scale there even on one of the screws on the case.


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## DavecUK (Aug 6, 2013)

1. Never assume it's not leaking from the top and running down (photos of the top)

2. Hi res great quality photos with good light

3. Run the boiler up to temp from cold whilst watching like a hawk, use a torch

4. Clean off that surface rust ASAP, and use a rust treatment for all non stainless (type that turns it black, or a converter)....you paint it on with a brush. https://www.amazon.co.uk/Loctite-Rust-Remedy-90-ml/dp/B000TAPAUG/ref=sr_1_7?keywords=rust+converter&qid=1570448951&sr=8-7

5. It has been leaking for a while for that to happen, Do annual checks on the machines and with any new espresso machine (to you) check every 4 months for the 1st year.* I recommend all machines have the case off top off and a quick torch inspection every 6 months, problems are often easier to deal with when caught early. *I know people say annually for maintenance, but top of and a quick look with a flashlight only makes good sense.

6. Always be mindful of any water under the machine and check weekly. if you find any identify where it came from e.g. drip tray splashes, overfilling etc..

If you do have to remove the boiler, it's not the end of the world a bit of a PITA, but not difficult....*just remember open ended spanners and use a second spanner, or very light panel pin hammer to use sharp raps to tap untighten any stubborn nuts (you are trying to shock them off with multiple sharp raps), don't use gorilla force to torque them off.*

I think that the Beta you bought for £450 from Paolo, and If I remember rightly you purchased it back in November, so if there are any parts you need you are still covered by the 1 year warranty he gave you. However, if it is one of the blanking nuts at the bottom of the boiler, they are best removed and refitted using 5-7 turns of PTFE tape on the threads. If it's leaking from the top then I don't know. If it's one of the elbows, then unless it's cracked, that again can be refitted using PTFE tape. If it's a PTFE tube, they can often have the grip nut tightened. If that doesn't work the tube can be cut straight with a Stanley knife (trim off 5mm) and then pushed on the fitting and secured with the clamp nut.


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## Hasi (Dec 27, 2017)

If it's not actually leaking from the boiler itself, take a look at the opening in front plate underneath group (where solenoid drain valve sits) from inside and out (take little drain valve cover off): on my Beta model I've had water jetting upwards after being released at the end of a shot (documented in Beta thread). From there it took two ways into the case: through aforementioned opening in front plate and between lower edge of front plate and base plate. This caused to trip RCD on multiple occasions. Went after it by sealing off front plate against base plate as well as closing opening behind drain valve cover with duct tape.

Good luck finding and repairing (if not still under warranty)!


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## mctrials23 (May 8, 2017)

coffeechap said:


> that doesn't look good, let's hope some of the other minima users can help, or ACS . Hope you get parts to fix it soon. Is this a beta machine?


 Its the beta machine that Dave had for testing so I think its probably identical to the other beta machines.



Rob1 said:


> Did you check for leaks when it arrived? Just to give any idea of when it started. In one of the pictures it looks like the part from the element is wet. Have you turned it on with the cover off as you should be able to see the leak by doing that?
> 
> In one of the pictures the insulation looks wet so it could be leaking from the top and dribbling all the way down the sides through the insulation to the bottom...
> 
> What kind of water are you using? Looks to be a lot of scale there even on one of the screws on the case.


 Didn't check when it arrived but it wasn't leaking then and it hasn't been leaking for more than a few months as the machine was moved a few months ago and there was no residue or wet patch underneath. Water is tesco ashbeck alone.



DavecUK said:


> 1. Never assume it's not leaking from the top and running down (photos of the top)
> 
> 2. Hi res great quality photos with good light
> 
> ...


 Cheers Dave, I tried to get as good pictures as possible but without removing the entire boiler that is almost impossible. To my eye the top looks fine but I am just adding a couple of photos. One of the steam and one of the brew boiler. There is stuff around the right angle (copper pipe) part but there is the same stuff on the brew boiler as well. I assumed that was normal.

Sounds like I need to get it apart a bit more, clean it up and then we should be able to check it out a bit better


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## mctrials23 (May 8, 2017)

Pictures of top of the boilers.

One other thing, I took the bolt out of the top of the steam boiler (one with the collar, i think it allows air to escape as pressure build) and the washer underneath just disintegrated. Any idea where the best place to find a replacement is? Is this something I should be talking to ACS about or is it a generic washer I can buy from anywhere?


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## DavecUK (Aug 6, 2013)

Can you use a free screen clipping package (windows has a free one) that allows you to put an identification arrow on the component you took off, I am not sure which one you mean.

A further check, bring it up to pressure against a blind filter using the brew switch and also look to see if anything leaks internally.

P.S. There are few if any washers used, usually sealant or PTFE thread and PTFE can always be substituted where sealant was used.

P.S. I checked the machine before he collected it, it wasn't leaking anywhere at that time.


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## Rob1 (Apr 9, 2015)

mctrials23 said:


> Didn't check when it arrived but it wasn't leaking then and it hasn't been leaking for more than a few months as the machine was moved a few months ago and there was no residue or wet patch underneath. Water is tesco ashbeck alone.


 Hasi made a good suggestion I think. If you can't see it leaking anywhere from the top or bottom of the boilers while the machine is heating and you can't see anything when the pump is running against a blind basket you could just be getting splashes from the solenoid drain valve.

The Betas needed modification to the drain valve to prevent splashing if I remember, and while the Beta I received after some time had the improvement made from the factory I recently found the machine was wet underneath the front panel; what happened to me was the kind of shower screen nut that screws on to the pipe under the valve had come unscrewed and was sitting loose at the bottom of the cover (too narrow for it to fall through) so when the shot was stopped the water was spat out at this nut and it splashed up inside the machine and ended up on top of the pump and around the bottom of the case. Managed to mop it all up with paper towels before any damage was done thankfully.

I asked what water your were using because it appeared to have caused scale to the screw bottom right in your 4th pic and on the bottom of the case towards the back. How often do you use the service boiler (time on) and how much milk do you steam a day, and do you ever remove water from the service boiler via the hot water tap?


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## ncrc51 (Mar 14, 2018)

Looks very much like my beta machine and the water that accumulated resulting in a corroded and overheated boiler wire. I felt that there was some leakage evident around two of the plugs in the bottom of the steam boiler. I removed them and the seal (rubber o ring?) had deteriorated on both of them. I suspect the best fix would be an appropriately sized silicone o ring which I did not have. I used a likely excessive amount of Teflon tape on the threads and around the grooved base of the plugs. This appears to have been successful. I have this machine in Nova Scotia and will be storing it for 6 - 7 months starting the end of November when we return to the US. I plan on bringing parts and supplies back in the spring to fully repair/replace the various seals on the boiler. I like the Minima. It was a beta and as expected has not been problem free. It makes good espresso. If at some point it becomes challenging to maintain, I likely would not replace it with another Minima.


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## mctrials23 (May 8, 2017)

DavecUK said:


> Can you use a free screen clipping package (windows has a free one) that allows you to put an identification arrow on the component you took off, I am not sure which one you mean.
> 
> A further check, bring it up to pressure against a blind filter using the brew switch and also look to see if anything leaks internally.
> 
> ...


 I have had a good look and brought it up to pressure a few times and its a couple of the bolts in the bottom of the steam boiler that are leaking. As Rob says, the washer has perished (cracked completely through in one place and generally cracking throughout) and this is letting water leak around them. I have tried to stick a load of PTFE tape around the leaking ones but so far I haven't had any luck getting them to seal properly under full steam pressure. Part of the thread on one of the nuts is snapped as well.



Rob1 said:


> Hasi made a good suggestion I think. If you can't see it leaking anywhere from the top or bottom of the boilers while the machine is heating and you can't see anything when the pump is running against a blind basket you could just be getting splashes from the solenoid drain valve.
> 
> The Betas needed modification to the drain valve to prevent splashing if I remember, and while the Beta I received after some time had the improvement made from the factory I recently found the machine was wet underneath the front panel; what happened to me was the kind of shower screen nut that screws on to the pipe under the valve had come unscrewed and was sitting loose at the bottom of the cover (too narrow for it to fall through) so when the shot was stopped the water was spat out at this nut and it splashed up inside the machine and ended up on top of the pump and around the bottom of the case. Managed to mop it all up with paper towels before any damage was done thankfully.
> 
> I asked what water your were using because it appeared to have caused scale to the screw bottom right in your 4th pic and on the bottom of the case towards the back. How often do you use the service boiler (time on) and how much milk do you steam a day, and do you ever remove water from the service boiler via the hot water tap?


 There is definitely some scale in there but i think its very very minimal. Literally just stuff that is suspended in the water as apposed to caked on the inside of the boiler. As above, its the bolts that blank off three of the holes in the bottom of the steam boiler that are leaking. The OPV venting is very powerful and does splash a bit but I haven't had any issues with that beyond the usual. The service boiler is usually on quite a lot. Probably from about 8:30 in the morning through until about 4:30 sometimes. Other times its off for half that time. Sometimes I use the hot water tap but perhaps a few times a month.



ncrc51 said:


> Looks very much like my beta machine and the water that accumulated resulting in a corroded and overheated boiler wire. I felt that there was some leakage evident around two of the plugs in the bottom of the steam boiler. I removed them and the seal (rubber o ring?) had deteriorated on both of them. I suspect the best fix would be an appropriately sized silicone o ring which I did not have. I used a likely excessive amount of Teflon tape on the threads and around the grooved base of the plugs. This appears to have been successful. I have this machine in Nova Scotia and will be storing it for 6 - 7 months starting the end of November when we return to the US. I plan on bringing parts and supplies back in the spring to fully repair/replace the various seals on the boiler. I like the Minima. It was a beta and as expected has not been problem free. It makes good espresso. If at some point it becomes challenging to maintain, I likely would not replace it with another Minima.


 Not going to lie, for the price I paid it is a steal but working on this thing is a bit of a nightmare. My beta machine doesn't go together that well with lots of pushing, torsion and goading required to seat various screws into their threads and you have to take the entire bottom plate off to work on it which in turn lets the electrics, steam boiler and water pressure plate float about. I am somewhat concerned that I will have a wire touching a very hot piece of metal somewhere as a result.

I think I would have preferred the minima to be a little larger and a little better laid out. Like you, I don't know if I would get another if this one packs in.


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## DavecUK (Aug 6, 2013)

I'm now getting confused. I keep asking for photos with arrows, what nut broke (how, was it a service boiler blanking bolt) what washer what collar? How did you wrap the thread, how many turns of PTFE, have you taken the boiler out, because that's how I understand it should be done to work on it, *not remove the entire bottom plate?*

PTFE should not be a problem for any or the boiler fittings and only needs to go on the threads, they are blanking plugs and you can actually use High temperature food grade sealant on them (although I have never found one I liked) but I prefer taking the time for PTFE and I don't wrap it around any grooves, just the thread.

I'll step back from this one for now as I can't visualise accurately what you have done, how you have done it and what you have done it to. I worry that any advice I give you without the right information may just make things worse.

P.S. Just in case....PTFE tape wrapped the wrong way on the thread rucks up and won't seal.


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## mctrials23 (May 8, 2017)

DavecUK said:


> I'm now getting confused. I keep asking for photos with arrows, what nut broke (how, was it a service boiler blanking bolt) what washer what collar? How did you wrap the thread, how many turns of PTFE, have you taken the boiler out, because that's how I understand it should be done to work on it, *not remove the entire bottom plate?*
> 
> PTFE should not be a problem for any or the boiler fittings and only needs to go on the threads, they are blanking plugs and you can actually use High temperature food grade sealant on them (although I have never found one I liked) but I prefer taking the time for PTFE and I don't wrap it around any grooves, just the thread.
> 
> ...


 Sorry, its all got a little convoluted. So initially I took off the pressure sealing bolt on the top of the steam boiler to drain it. See picture 1 with the broken washer next to it. That seems fine with some PTFE tape on the thread even if I wouldn't expect a washer to perish with less than a years use. That was just an annoyance and not the cause of any problems.

The issue is with the blanking bolts at the bottom of the steam boiler leaking. Picture two is of the seal that has cracked and I have removed from the nut. I have put anywhere between 2 and 5 wraps of PTFE tape around the leaking nuts with no success and every time I do this it takes a few hours because I have to wait for it to heat up and cool down between tests and if I want the machine to be a little easier to manage I am filling and draining the boiler each time.

Im making sure I wrap the PTFE the correct way around the threads.

The only way to work properly on the bottom of the boiler is to completely remove the bottom plate as there are a number of pipes and connectors that go into the bottom of the boiler that connect to the rest of the machine. Without access to undo those, you cannot remove the boiler or access many of the parts of the steam boiler at the bottom. The plate the water bottle sits on bolts into the floor of the machine and doesn't connect anywhere else. The same with the steam boiler. The steam boiler is held in place by the three legs bolted into the bottom plate along with the various pipes that link it to the rest of the machine. Does that make sense?

Ive added a final picture circling the bolts on the bottom that are causing the leaking.


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## DavecUK (Aug 6, 2013)

1st photo is of the Vacuum breaker, I always put those in with PTFE tape....

Rubber/Silicon washers shouldn't be used on boiler fittings like those nuts. Viton might be OK, but are less common and those sort of fittings are often torqued up to tight for a washer anyway, so it's not surprising they perish. I know they use a Threadsealer now (just found out). They only used o ring type washers on beta machines.

Blanking nuts - 2 turns of PTFE tape is not enough for threads that coarse (same for vacuum breakler threads), *you need at least 5 turns if not more*...remember it's not about how tight the bolt is, PTFE does not care about how tightly it's torqued up. There should be enough PTFE on the thread that it's fairly tight all the way in and they should only be slightly nipped up, not tightened down. Overtightening with PTFE tape actually creates more chance of a leak. Get as many turns of PTFE on the bolt that allows it to be screwed in (if that's 7 great, if you can get 9 on and still screw it in use 9.

I have secured dozens of boiler fittings with PTFE

For the blanking nuts If you want to use crush copper washers you can, but they do have to be torqued down to seal, the link shows the sort of things, you can find them cheaper on amazon but theres a starter for 10.

https://www.amazon.co.uk/120Pcs-Solid-Copper-Washers-Assortment/dp/B074SFV5R9

If you want to seal with O rings, sealing surface must be clean and use FKM (otherwise known as Viton), do not get Green ones that are HNBR, they are no good. With an O ring, the fitting must only be lightly snugged up so you don't crush the o ring badly.

https://www.amazon.co.uk/1-9mm-Section-VITON-Ring-Gaskets/dp/B07DL8LW1K/ref=sr_1_7?keywords=viton+o+ring&qid=1570538359&s=diy&sr=1-7

I am 100% sure, but stand to be corrected that boiler removal would have been better than removing the bottom plate, but at least you are able to quickly reheat the boiler I guess. don't worry about wires touching the surface of the boiler, the heat won't affect them.

P.S. Other Beta machine owners need to be aware and check their machines for leaks every 3 months and fix immediately.


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## mctrials23 (May 8, 2017)

DavecUK said:


> 1st photo is of the Vacuum breaker, I always put those in with PTFE tape....
> 
> Rubber/Silicon washers shouldn't be used on boiler fittings like those nuts. Viton might be OK, but are less common and those sort of fittings are often torqued up to tight for a washer anyway, so it's not surprising they perish. I know they use a Threadsealer now (just found out). They only used o ring type washers on beta machines.
> 
> ...


 Thanks as always Dave. I'm still confused as to how you would remove the boiler without removing the bottom plate. To remove the boiler you have to remove the various gubbins at the top of the boiler and then you have to remove at least 3 nuts from various pipes going into the bottom of the boiler. Those nuts at the bottom are inaccessible with the bottom plate still attached. I'm not talking about the 3 legs the boiler sits on that bolt through the bottom of the case, I'm taking inlet/outlet pipes and connectors.

I have contacted Paolo about this to see what he thinks but for now I will have a look at getting some of the above copper o-rings.


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## DavecUK (Aug 6, 2013)

The ones that are not flexible you can reach, the others are PTFE pipe and flexible once the boiler is loose...or perhaps I am remembering the Betas wrongly? Still if the bottom plate is off it's off now I guess.


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## L&R (Mar 8, 2018)

Disregarding leaks that could happen on every single machine why there are so many non SS/brass nuts, bolts etc in Minima. This picture is lil bit frightening.


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## ncrc51 (Mar 14, 2018)

The picture of the "blanking nuts" gasket/seal looks exactly like mine when I disassembled the machine. BTW I did not need to remove the bottom plate to remove the steam boiler. I did something like Dave suggested with about 5 turns or so of tape and did not over tighten the nuts.


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## ajohn (Sep 23, 2017)

Copper washers need to be tightened to a set torque and don't sound like a brilliant idea to me for items that are for ever getting hot and cold. O rings can be fine but in that sort of situation but the pressure on them really needs to be set mechanically not by tightening up until it seems right. Groove on the underside of the plug etc to set the compression. That needs to be sized correctly - dissimilar metals for instance in this case with different expansion rates.

I'd go for ptfe tape.  Not the one the gas safe lot have dreamed up that is thicker. It's tricky to stretch it into the thread and get to stay in place. They seem to have spec'd it so that they can dictate 2 turns. LOL if it was stretched enough it would need 3.

John

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## DavecUK (Aug 6, 2013)

L&R said:


> Disregarding leaks that could happen on every single machine why there are so many non SS/brass nuts, bolts etc in Minima. This picture is lil bit frightening.


 Because some stainless will get surface rust eventually, some bolts on betas were not stainless as were some parts. *It's common on many espresso machines* e.g. Rockets have a Mild black painted steel frame, as do Fracinos, la Spaz, ECM etc etc.... and all machines have non stainless bits that can rust. *ACS are unusual in that they use an all stainless steel case and frame* (unless they are powder coated). perhaps when he has cleaned it up it will look less frightening. It's a simple repair job that's just a little tedious....annoying when I feel they really shouldn't have tried sealing o rings unless they were Viton.

Looks like the washers on the posts, the feet threads/heads and 1 earthing strap nut and bolt are not stainless. I would imagine it's easy enough to sub stainless for a few pieces and when Paolo reads this I am sure he will, unless he has already done so on production models.

All machines with mild steel in the interior especially if it's used as a base frame can rust, I've seen almost new machines with rist where the drip tray or a vent leaks down onto mild steel. I even sealed one machine @hotmetal under the drip tray so it wouldn't happen.


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## L&R (Mar 8, 2018)

Thank you Dave, I know these machines that are on mild steel frames, but did not expect so many rusty bits in Minima it looks like 10 year old.


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## mctrials23 (May 8, 2017)

Its not good in places but some of that is just staining/rust water. Not super impressed in general as more than one of the bolts is leaking and its proving hard to get any sort of seal on them now. I just tried again with 8 wraps of PTFE and its still leaking.


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## DavecUK (Aug 6, 2013)

mctrials23 said:


> Its not good in places but some of that is just staining/rust water. Not super impressed in general as more than one of the bolts is leaking and its proving hard to get any sort of seal on them now. I just tried again with 8 wraps of PTFE and its still leaking.


 Get as many turns on as you can but are still able to screw them in, if that's more than 8 use more. If you can't get any more on and screw them in I have no idea why it's not sealing because it should on a clean thread?


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## DavecUK (Aug 6, 2013)

L&R said:


> Thank you Dave, I know these machines that are on mild steel frames, but did not expect so many rusty bits in Minima it looks like 10 year old.


 Are you trying to help the other person or just clutter up his thread by re quoting photos he has already posted and comments that I think in no way help him?


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## mctrials23 (May 8, 2017)

As you can see in this picture, albeit not massively clearly, the thread on this bolt has snapped off in places. I wonder if this is why its not sealing up any more.


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## El carajillo (Mar 16, 2013)

It looks more like ' blanking plug' rather than a bolt with a reduced shoulder for an 'O' ring. The end of the thread looks more like machined off rather than broken.


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## El carajillo (Mar 16, 2013)

A well fitting "teflon" washer would probably work well to seal it. As a temporary measure OR possibly permanent, an old plumbers trick is to make a 'grommet' with PTFE tape.

Unwind about 50 cm of tape and twist this into a tight spiral string. Wind this into the recess under the head until it is virtually flush with the out side of the head, wind normal tape onto the thread section and refit nipping up firmly. :good:


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## Rob1 (Apr 9, 2015)

Hasi said:


> Rob1 said:
> 
> 
> > There's a difference between joining the conversation and detracting from it. OP has a serious problem to solve. If you or anyone else wants to complain about their machine rusting or has concerns that it might, they should start another thread instead of crashing this one or cluttering it with impertinent crap like I've quoted above and written here in response.
> ...


 It's nothing to do with human rights or free speech. The whole idea of a forum and threads is to create designated spaces for discussions. This thread is about a leak from the boiler of beta minimas and how to fix it. You wouldn't go into the lever forum and start posting threads about non lever machines, or pop into the sale forum to start talking about what you had for dinner and then claim "oh I believe in freedom of speech and human rights so I'm going to discuss things wherever I want". The whole point of moderators is to move threads to proper forums, and keep discussions on topic by splitting unrelated posts into new threads so discussions can continue. That's what 'cleaning up' is... there's already a thread for feedback on beta minimas. If anyone has criticism of production models they should start a new thread and make their comments there.


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## Rob1 (Apr 9, 2015)

Hasi said:


> well then let's carry your agenda over to the forum rants thread then.
> 
> I've contributed in here as I happen to have a beta machine that's been getting wet feet as well. How about you?


 Yes, along with all other unrelated posts.

No. I've got the solenoid drain thingy and newer OPV on mine so maybe I've got sealant on the bolts too, there's probably no way to know without removing them so I'll just watch out for leaks instead. Only problem I had was the thing falling off the solenoid drain. I'm more interested to find out the size of the replacement bolts op looks like they'll need than anything as that might be useful for people in the future myself included.

@MildredM not really sure on the rules, just assumed discussions should be kept on topic regarding fixing the leak. Regardless could you remove the posts I've made that aren't on topic at least?


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## Cooffe (Mar 7, 2019)

@DavecUK just for my own clarification for future maintenance - the black O-ring that is cracked, is the purpose to stop heat transfer and thermal expansion on the bolt or provide a seal to the boiler - or is it both of them? Also, why is HNBR not recommended - for heat?



El carajillo said:


> It looks more like ' blanking plug' rather than a bolt with a reduced shoulder for an 'O' ring. The end of the thread looks more like machined off rather than broken.


 The blanking bolt has a leading edge on it that's tapered with a shoulder so yeah I think it is machined like that. I think it might be a rolled thread instead of cut by the looks of it. Not quite sure what that bolt does - probably for the boiler manufacturing process. The boiler I think is 316 Stainless so should be more than suited for the environment it is in. I think the culprit is in this bolt. Maybe it needs to be a grade B7 stainless or titanium bolt to reduce Stress Corrosion Cracking?


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## Norvin (Sep 10, 2014)

Its quite common for the last few millimeters of a thread to be left off in manufacturing a bolt (or more correctly, a set screw), it would be hard to machine or roll a thread right up to abut the head so the diameter of the shaft is reduced to the thread root diameter so that it can be screwed fully in. It looks like when you omitted the washer only a small amount of thread was engaged in the boiler and even damaged the last portion of thread.

I would try a dowty (or bonded seal) washer, it would restore the missing thickness and also incorporates a seal. They can be found on ebay. Worth a try.


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## Cooffe (Mar 7, 2019)

Fair enough. If the bolts aren't B7 grade stainless I'd expect them to crack under pressure/heat, especially if the reservoir isn't filled with water that has low chlorine levels (ie just filled with tap water). Happy to be proven wrong though.


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## ajohn (Sep 23, 2017)

Hasi said:


> well then let's carry your agenda over to the forum rants thread then.
> 
> I've contributed in here as I happen to have a beta machine that's been getting wet feet as well. How about you?


 Did anyone notice the word *BETA. What the word means is that producers think it's ready for production. ie Most or all issues ironed out but can't be 100% sure. *Not the easiest of things to do on an espresso machine as numbers are relatively low. I used to get beta releases of Windows. Enormous numbers and resources and things could still be wrong with it.

Really all criticism should be directed at the manufacturer who in this case might help but on the other hand they were sold at a very reduced price. The result of that would be far more useful than bleating on here. ie What do they do if there are problems with early machines. I looked at buying a machine that has been on the market for some time. It's had 4 release versions. Early ones did have reported problems.There is nothing unusual about this.

Them comes Dave himself. There will be similar people involved in all espresso machines. You are fortunate to be able to talk to him. He looks at machines and forms opinions about them and in some cases that may mean manufacturers making changes. Past that he is out of the loop. The retailers should be reporting problems back to the manufacturer once they are being sold.  There is a video from Whole Latte Love bleating about some aspects of that. They help sort out new models and later others start selling them. They may be unusual. In my experience in other areas of what I call the big boys toys market the retailers often don't give a toss. Being fair though often they are selling items that are much cheaper than what could be called the real thing and people can't afford those.

LOL While Dave is doing all of this he is making oodles of money and etc. What people can believe always amazes me. He has opinions. For instance E61 heads are wonderful. Personally I think they belong in the dark ages. He is aware of a number of aspects about espresso machines so in many ways gives good advice. I asked about a particular machine on here and he replied. He has never been near one so it can only be opinion - it's just not the style of machine he would have anything to do with.

Many people on here are also using a beta product. It's called Niche. There is no way Dave can determine it's likely life. He's tested what he has tested and we have bought what we have bought. Past that it's all down to Niche. An espresso machine is no different. The most interesting aspect in this area really is how the manufacturer responds. They should all have some one prepared to at least respond.

Looking at replies cropping up - lets stick to the point, the seal has failed. If something has actually cracked off the plug in use it will still be about. I'd say that at the temperatures in espresso machines the chances of any normal stainless doing that are incredibly low and a plug would most likely be made of a free cutting variety. I mentioned dissimilar materials earlier only because I thought the lug was brass but other photo's show it isn't.

John

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## ajohn (Sep 23, 2017)

Nikko said:


> The Minima Beta thing was a pure marketing exercise. The Minima is strung together with standard parts that have been in use for decades and there is nothing innovative about it that needs testing or development. Unless of course the company is so useless that it does not know how to blank off a few holes.


 Your and expert then?

John

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## coffeechap (Apr 5, 2012)

For what it is worth, I think that there is some healthy discussion on here intermingled with some other snipes back and forth. People are coming up with plausible solutions and others are highlighting other deficiencies that are relevant to the machine in question. I am sure that being an advocate of open discussion, Dave won't be bothered by this discussion, he has been involved in its development and is ultimately not responsible for any issues that are subsequent to his input, however ACS are and the way THEY react to this is key in restoring faith in THEIR product.


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## MildredM (Feb 13, 2017)

Has anyone copied @Paolo_Cortese in for advice?


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## ajohn (Sep 23, 2017)

Norvin said:


> Its quite common for the last few millimeters of a thread to be left off in manufacturing a bolt (or more correctly, a set screw), it would be hard to machine or roll a thread right up to abut the head so the diameter of the shaft is reduced to the thread root diameter so that it can be screwed fully in. It looks like when you omitted the washer only a small amount of thread was engaged in the boiler and even damaged the last portion of thread.
> 
> I would try a dowty (or bonded seal) washer, it would restore the missing thickness and also incorporates a seal. They can be found on ebay. Worth a try.
> 
> View attachment 32657


 Not a bad idea but an FPM one would be a good idea for temperature resistance especially on the steam boiler which if I recollect correctly runs at a higher pressure. They cost a bit more but reckoned to be ok to maybe 200C not 100 as per usual dowty. eg

https://www.barnwell.co.uk/catalog/product_info.php/products_id/7840/osCsid/33dmpi78b5fn96pshbajcjdlt4

True Viton pass - look at their specs.

Edit - and do check I am correct about the increased temp spec. Pretty sure I am but ...................

John

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## Cooffe (Mar 7, 2019)

ajohn said:


> Not a bad idea but an FPM one would be a good idea for temperature resistance especially on the steam boiler which if I recollect correctly runs at a higher pressure. They cost a bit more but reckoned to be ok to maybe 200C not 100 as per usual dowty. eg
> 
> https://www.barnwell.co.uk/catalog/product_info.php/products_id/7840/osCsid/33dmpi78b5fn96pshbajcjdlt4
> 
> ...


 Surely temp. requirements would be based off the ASTM D2000 callout for the rubber grade. Wouldn't just rely on it being "FKM" or "Viton" or "FPM" to give it enough credibility that it's temperature stable to 200 deg.C.


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## jimbojohn55 (Jan 15, 2016)

Looking at the pictures it may be an issue with the proximity to the heating elements which are slightly proud of the base, PTFE washers are good to 260 C


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## El carajillo (Mar 16, 2013)

MildredM said:


> Has anyone copied @Paolo_Cortese in for advice?


 @Paolo_Cortese often looks in on the forum, I am sure someone has contacted him and I am surprised that he has not responded to the discussion


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## mctrials23 (May 8, 2017)

I have emailed Paolo about this and have taken various bits of advice on board from this thread so thanks for everyones input. I will report back once I have fixed this which should help others and allay any fears people have about the machines.


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## ajohn (Sep 23, 2017)

Cooffe said:


> Surely temp. requirements would be based off the ASTM D2000 callout for the rubber grade. Wouldn't just rely on it being "FKM" or "Viton" or "FPM" to give it enough credibility that it's temperature stable to 200 deg.C.


 It's a problem. There are several grades of Viton which is an FKM for instance and several grades of that as well. The curious aspect is that hot water and steam are bad news for most types of usable seals. All things that can be used are likely to swell and degrade to some extent so are likely to have an end of life.

I spent ages looking at what could be used in Sage machines. There isn't an answer. Alternatives could be likely to have problems what ever is used and for other reasons I don't blame them for using what looks to be food grade silicone but it could be any grade. They appear to last for over 3 years in what is a pretty nasty environment but the compression is well controlled. Then I asked myself how many machines develop leaks at some point how ever they are put together. Even flared tube set ups do.

This one may have failed because it was overtightened. Same material what ever it is may have been fine used in other machines. Sh#t happens and espresso machine makers can't do what my automotive lot get up to. Spend millions and still have whoopsies. Sighs of relief if little crops up during warrantee - it does sometimes. If this aspect on the machine is changed it will take a long time to how well it works.

As it's pid I would have thought the boiler casing temp wont depart by much from the temperature of the water in it.

John

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## Cooffe (Mar 7, 2019)

ajohn said:


> It's a problem. There are several grades of Viton which is an FKM for instance and several grades of that as well. The curious aspect is that hot water and steam are bad news for most types of usable seals. All things that can be used are likely to swell and degrade to some extent so are likely to have an end of life.
> 
> I spent ages looking at what could be used in Sage machines. There isn't an answer. Alternatives could be likely to have problems what ever is used and for other reasons I don't blame them for using what looks to be food grade silicone but it could be any grade. They appear to last for over 3 years in what is a pretty nasty environment but the compression is well controlled. Then I asked myself how many machines develop leaks at some point how ever they are put together. Even flared tube set ups do.
> 
> ...


 Yeah I agree with what you're saying. There's shortfalls in everything, especially when in harsh environments. I suppose as Engineers the job is to mitigate the failures and make sure it manifests itself just as a leak instead of anything a bit more dangerous. Suppose that it's part and parcel of owning a serviceable item, which has perishable parts.

Also - you don't happen to work for one of the large automotive OEM's in the west mids. do you? Just noted where it says you're located and you just said about your automotive lot!


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## ajohn (Sep 23, 2017)

Cooffe said:


> Yeah I agree with what you're saying. There's shortfalls in everything, especially when in harsh environments. I suppose as Engineers the job is to mitigate the failures and make sure it manifests itself just as a leak instead of anything a bit more dangerous. Suppose that it's part and parcel of owning a serviceable item, which has perishable parts.
> 
> Also - you don't happen to work for one of the large automotive OEM's in the west mids. do you? Just noted where it says you're located and you just said about your automotive lot!


 Yes. I'm a slave and was sold 3 times but now retired. OEM, not actual making cars

John

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## El carajillo (Mar 16, 2013)

Has there been any resolution or solution to the leak and other discussion on this machine ? All seems to have gone quiet.


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## DavecUK (Aug 6, 2013)

El carajillo said:


> Has there been any resolution or solution to the leak and other discussion on this machine ? All seems to have gone quiet.


 I took it offline with the person so I could help them properly....too much irrelevant noise on this thread by a few people with an agenda. He has fixed it now with a little guidance from me. Some people need to think more about the person that needs help and not their own personal agendas...


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## El carajillo (Mar 16, 2013)

Thank's for the update, how did he cure the leak in the end, various suggestions were put forward.

As you yourself said some time ago, it is better if the thread is kept on the forum in order to help others who have the same or similar problem.

Remarkably quiet from Paolo Cortese,a word from him would probably have been appreciated.


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## DavecUK (Aug 6, 2013)

El carajillo said:


> Thank's for the update, how did he cure the leak in the end, various suggestions were put forward.
> 
> As you yourself said some time ago, it is better if the thread is kept on the forum in order to help others who have the same or similar problem.
> 
> Remarkably quiet from Paolo Cortese,a word from him would probably have been appreciated.


 Paolo will be remarkably busy preparing for Milan host 2019. The huge food beverage and coffee exhibition, plus clearing up the fallout from the factory move..

He cured the leak by using a few UK parts I linked him to and some PTFE, but I won't go into too much detail now because care has to be taken using my solution. I explained to him exactly how he needed to go about it and it worked. I suspect all users with O rings will eventually have to implement the same solution apart from @ncrc51 in the USA because he did his much longer ago. I could explain technically what's happened, why it doesn't affect production machines and the science behind what happened to his plug...but I can't be arsed to do it here and have a certain element start creating trouble. I will post the technicals on the ACS owners forum, it can be made a sticky resource and remain clear of shite....

It will have to wait a few weeks as I have a pre-production machine from Crem (quite an advanced machine) on the bench that needs an engineering review (not a public review) and there's very short timescales for a first cut...They are launching it at Host, will probably want to meet Milan (I am out there anyway) to discuss the review and perhaps I get to meet the tech team. So I have a lot to do before I fly out on 16th Oct, I will post the solution and the science of what happened when I get back a week later.


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## Rob1 (Apr 9, 2015)

Cooffe said:


> My bad - I'll make a Birmingham thread next time...


 Would probably be more appropriate to send a private message.


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## DavecUK (Aug 6, 2013)

Cooffe said:


> Is it time for another discussion on Birmingham to derail this topic too? ???


 I think so.....you go for it. The solution won't be posted on here by me, so it really doesn't matter what happens to this thread.


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## Nicknak (Aug 10, 2018)

It seemed to be a pretty simple plumbing issue , @norvin seemed pretty on point .


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## mctrials23 (May 8, 2017)

The machine is fixed, cleaned up and back it one piece now. I ended up buying replacement stainless steel bolts to go into the bottom of the steam boiler and those coupled with PTFE has fixed everything.

The reason lots of PTFE wasn't working was because the threads on some of the bolts had perished. I believe that on the production machines these bolts are coated in something which removes the issue but on the beta machines they are held in with the threads and some sort of washer (plastic maybe). Due to the material the bolts were made from and the nature of an increasingly (I can't remember which way it goes) acidic or alkaline solution from constant heat applied to a relatively stale body of water, the threads weakened and broke in places leading to the leaks. Replacing the bolts was very easy and although I got very frustrated on the way to the solution when simply re-using the dud bolts and lots of PTFE didn't work, the replacement bolts sorted the issue very nicely.

Dave helped me with the bolts to buy and explained how to install them without causing any damage to the boilers threads as the bolts are not a perfect 1:1 replacement for the originals but they are very close.

Apologies for the lack of responses for a few days but I have been busy and only just got everything put back together this afternoon after fixing it yesterday.

The rust etc cleaned up fine and most of it was just deposits from a few parts that actually rusted like a bolt that held a couple of cables to ground on the case.

I'm sure that I have got some of the above incorrect from a technical standpoint but that is my basic understanding of the issue.


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## Cooffe (Mar 7, 2019)

So I was right with it being SCC... the chlorine and temperature cycling caused it... I guess (hope) the bolt you have now is a grade B7...

Regardless I'm glad it's back up and running for you!


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## Rob1 (Apr 9, 2015)

Cooffe said:


> So I was right with it being SCC... the chlorine and temperature cycling caused it... I guess (hope) the bolt you have now is a grade B7...
> 
> Regardless I'm glad it's back up and running for you!


 Chlorine?


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## Hasi (Dec 27, 2017)

Rob1 said:


> Chlorine?


tap water maybe


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## Cooffe (Mar 7, 2019)

Rob1 said:


> Chlorine?





Hasi said:


> tap water maybe


 As Hasi says - Chlorine is quite common in tap water to purify it. Boilers I believe are susceptible to alkali environments in SCC which the Chlorine would cause.

As far as I'm aware, not a lot of Chlorine is require to micro fracture and the cracks can then propogate severely under thermal cycling/loading. This - along with pressure - is quite clearly a perfect storm for cracks to develop and ultimately cause a fracture somewhere.


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## Rob1 (Apr 9, 2015)

Op used Ashbeck exclusively. High concentrations of chlorides and sulphates could develop from not flushing the service boiler regularly enough. My chemistry my be wildly off but you might get calcium sulphate deposits eventually. No chlorine though.


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## MediumRoastSteam (Jul 7, 2015)

I don't know if this is relevant to the posts above, but Ashbeck has 14mg/l of chloride. Note: chloride, not chlorine.


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## El carajillo (Mar 16, 2013)

Is it the thread on the plug OR the thread in the boiler or both which have been eaten away ? Are the 'NEW' bolts (plugs) a different thread form or a different size ?

Are these new bolts cutting their own threads ?


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## ajohn (Sep 23, 2017)

Cooffe said:


> So I was right with it being SCC... the chlorine and temperature cycling caused it... I guess (hope) the bolt you have now is a grade B7...
> 
> Regardless I'm glad it's back up and running for you!


 The boiler itself too ?

John

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## Rob1 (Apr 9, 2015)

ajohn said:


> The boiler itself too ?
> 
> John
> 
> -


 There no chlorine in the water...though I think the idea was right.

I asked what water was used, how often steaming was used, and how often the boiler was flushed (by asking how often the hot water tap was used) because I noticed scale on the bottom plate and screws which shouldn't happen with boiler safe water....So the service boiler water was probably supersaturated with minerals without ever being flushed properly meaning the 14mg/l Chloride from Ashbeck could rise significantly over the course of a year.

It's possible for SCC to occur even in 316L steel with high chloride concentration.


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## mctrials23 (May 8, 2017)

I don't use the hot water tap very often in general. The amount of scale in the boiler was very minimal when I looked in there as well.


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## MediumRoastSteam (Jul 7, 2015)

mctrials23 said:


> I don't use the hot water tap very often in general. The amount of scale in the boiler was very minimal when I looked in there as well.


The consensus is that you recycle the water from the service boiler now and again, irrespective of machine. Otherwise, the minerals will precipitate to the bottom of the boiler as Rob describes in one of the previous posts.

Sent from my iPhone using Tapatalk


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## ajohn (Sep 23, 2017)

Rob1 said:


> There no chlorine in the water...though I think the idea was right.
> 
> I asked what water was used, how often steaming was used, and how often the boiler was flushed (by asking how often the hot water tap was used) because I noticed scale on the bottom plate and screws which shouldn't happen with boiler safe water....So the service boiler water was probably supersaturated with minerals without ever being flushed properly meaning the 14mg/l Chloride from Ashbeck could rise significantly over the course of a year.
> 
> It's possible for SCC to occur even in 316L steel with high chloride concentration.


 I was making the point that I understand the boiler is stainless as well so if the bolt suffered from this problem the boiler will as well.

Then later in the thread yet another dig at Dave. He might be thinking whoopee a trip to Italy not boasting. What he does is looks at espresso machines for decent design features. You really expect him to get involved with specifications of items like bungs and gaskets. That area is down to the manufacturer and in this case it seems they got it wrong probably down to minimising the cost of the machine which is the whole idea of it and why it uses some one else's boiler. That I would assume is also used in another brand of espresso machine that has the same problem if the element fails and will also have the same problem if the part becomes unavailable. And as to the parts - do you have them in your hand or are you clairvoyant.

John

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## Rob1 (Apr 9, 2015)

ajohn said:


> I was making the point that I understand the boiler is stainless as well so if the bolt suffered from this problem the boiler will as well.
> 
> Then later in the thread yet another dig at Dave. He might be thinking whoopee a trip to Italy not boasting. What he does is looks at espresso machines for decent design features. You really expect him to get involved with specifications of items like bungs and gaskets. That area is down to the manufacturer and in this case it seems they got it wrong probably down to minimising the cost of the machine which is the whole idea of it and why it uses some one else's boiler. That I would assume is also used in another brand of espresso machine that has the same problem if the element fails and will also have the same problem if the part becomes unavailable. And as to the parts - do you have them in your hand or are you clairvoyant.
> 
> ...


 Don't forget this is a beta machine, not a production one. Production machines won't have this problem because they have been sealed properly with threadlocker (and a coated bolt?).

It's seems careless of ACS to not inform Beta users that they need to remove the bolts and refit them with PTFE or threadlocker. They must have known the plugs on the beta machines would eventually fail otherwise they wouldn't have changed it for the production models. Beta machines were made with some parts they had on hand so I can understand this kind of solution was taken on them to keep costs down, but it wouldn't have cost them anything to raise the flag here.


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## ashcroc (Oct 28, 2016)

Rob1 said:


> Don't forget this is a beta machine, not a production one. Production machines won't have this problem because they have been sealed properly with threadlocker (and a coated bolt?).
> It's seems careless of ACS to not inform Beta users that they need to remove the bolts and refit them with PTFE or threadlocker. They must have known the plugs on the beta machines would eventually fail otherwise they wouldn't have changed it for the production models. Beta machines were made with some parts they had on hand so I can understand this kind of solution was taken on them to keep costs down, but it wouldn't have cost them anything to raise the flag here.


This isn't just a beta machine but the first one Dave put through it's paces. The fact things changed on the production machines had alot to do with the testing of this one.


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## mctrials23 (May 8, 2017)

That depends if a decision was made to change the style of fitting because of a known issue or simply as a more permanent fixture. A plastic washer is not a great long term solution whereas some sort of thread sealant is probably much better. I can't imagine that it was changed for malicious or nasty reasons. The number of beta machines is tiny and there would be no issue with contacting the owners and saying "there can be an issue with the bolts, here's some replacements. Replace them if you wish." I haven't seen anyone else with the same issue so it's clearly not a massive show stopper.

I feel like plenty of machines will change over time from their first iteration. Time exposes issues and weaknesses and things you don't necessarily foresee. I'm a software developer and you would be amazed at the inventive way people break software. When you build something it's easy to have blind spots when it comes to how people might use your product.


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## Dave S (Aug 3, 2020)

I know this is an older thread, but I had a question about this machine. My boiler died and ACS sent me a new brew boiler as a replacement. I successfully got the old boiler out, but the 90 elbow wouldn't budge when I tried to remove it with a wrench. Too much force was applied and it actually caused it to bend the threads inward where the connection to the brass collar and copper tubing pressure fitting is. I now need a new elbow and would honestly prefer just buying two new ones. Taking them off is quite hard with the tools that I have. Can anyone tell me what 90 degree elbows this ACS minima brew boiler uses? I've looked at the parts list online, but none of those exploded views actually list a part number or even mentions the elbows.

Thanks!


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