# Disembowelling the Vesuvius



## catpuccino (Jan 5, 2019)

Hi,

With the help of @DavecUK over on the owners forum we've diagnosed a blocked non-return valve as warm water is returning from the brew boiler into the water tank. Eek. Dave's doing a great job holding the fort over there, so thought I'd move disassembly questions over to here. n .

The machines otherwise looking really good, as it came from a small cafe business I hope the water used was relatively safe but as it stood unused for a long period I suspect that'd be time for a buildup anyway. It was also 'gigged' a few times at events, so potential for foreign objects to enter the system that way too.

Here's the part I need to get to:









What I'm wondering is, if that brass nut is the only thing securing the manifold to the body am I better off trying to get to the valve by removing or moving to one side the plate (right side) that holds the cigar box and various electronics, undoing the nut and trying to manoeuvre the manifold so that I can get access to remove the non-return valve or am I resigned to removing at least the brew boiler (left side) for access?

Pic for reference...


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## El carajillo (Mar 16, 2013)

I am not familiar with this machine BUT From what I can see I would remove the boiler and ancillaries to access the valve. There do not appear to be any connections behind the valve and the only retainer appears to be the brass nut with the sealing cap above it.

Note and photograph all pipe and cable connections from various positions. Remove the boiler, remove the cap nut then the retaining nut. This should give you sufficient room to manoeuvre the valve out. :good:


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## catpuccino (Jan 5, 2019)

El carajillo said:


> I am not familiar with this machine BUT From what I can see I would remove the boiler and ancillaries to access the valve. There do not appear to be any connections behind the valve and the only retainer appears to be the brass nut with the sealing cap above it.
> 
> Note and photograph all pipe and cable connections from various positions. Remove the boiler, remove the cap nut then the retaining nut. This should give you sufficient room to manoeuvre the valve out. :good:


 Thanks for this. I had a quick look before dinner at going in via the right side but ended up agreeing with you and deciding to remove the boiler.

That's probably an after dinner job...


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## catpuccino (Jan 5, 2019)

Chickpeas deployed.


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## catpuccino (Jan 5, 2019)

@DavecUK is it actually possible to remove the brew boiler without the steam boiler? Just looking at clearence between the case and the thermosyphon pipes....


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## DavecUK (Aug 6, 2013)

Yes, I removed my brew boiler to replace the heating element o ring. It's quite easy.


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## catpuccino (Jan 5, 2019)

DavecUK said:


> Yes, I removed my brew boiler to replace the heating element o ring. It's quite easy.


 phew. good on ya if you call that easy, though mostly it's the fear which is a problem ?


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## catpuccino (Jan 5, 2019)

Righty tighty lefty loosey right?? Damn this thing is jammed.


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## Border_all (Dec 19, 2019)

Try sharp taps if you could get ring spanner round end use a ring instead of open ended


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## Border_all (Dec 19, 2019)

Sorry you are sure the the silver part is not the part that unscrews and the nut you highlight is so you can hold it steady


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## catpuccino (Jan 5, 2019)

Thanks, taps not getting the job done. Here's what it actually looks like. I'll defer to @DavecUK about that but I'm having trouble with both.


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## DavecUK (Aug 6, 2013)

You could try injecting some concentrated descale in there. Really though get the valve apart.

You might have to remove the distributor to do it?


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## catpuccino (Jan 5, 2019)

DavecUK said:


> You could try injecting some concentrated descale in there. Really though get the valve apart.
> 
> You might have to remove the distributor to do it?


 It's definitely the bronze nut that unscrews? Hoping to avoid having to take it out but it's feeling more and more like I might have to.


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## Border_all (Dec 19, 2019)

Hi guys i am sure you have forgot more than i know and not followed from start. Before i removed more apart i would have a go with ring spanner on the brass part and open ended on the silver part use the silver as a steady spanner and you could exert more pressure on the brass without twisting all apart. You could also try applying light heat from hot hair dryer or such trying for expansion of the metal as it looks like ptfe tape on the brass fitting. Not trying in anyway to disrupt the thread ?


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## DavecUK (Aug 6, 2013)

I think so, you could write to Paolo and ask but I can't think why else it would have flats on?


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## El carajillo (Mar 16, 2013)

It looks like the brass nut could be a reduction bush ?


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## catpuccino (Jan 5, 2019)

Thanks all. Put a hell of a lot of force onto this tonight and no give at all. Might step back, re-evaluate tomorrow.

Also I've emailed Paolo re the correct approach.


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## El carajillo (Mar 16, 2013)

Pair of water pump pliers or adjustable spanner on the body of the valve behind the nut / bush and a ring spanner on the bush OR component. USE in a scissor action applying pressure too both tools == no pressure / force on anything else.


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## DavecUK (Aug 6, 2013)

I also think they might use thread sealant on that part...because you really don't want it to leak on an assembled machine when bench testing!


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## catpuccino (Jan 5, 2019)

DavecUK said:


> I also think they might use thread sealant on that part...because you really don't want it to leak on an assembled machine when bench testing!


 ?‍♂I miss the enthusiasm you get when first starting to disassemble something.


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## catpuccino (Jan 5, 2019)

Well.

Turns out I've every size of ring spanner except the one I need, and really struggling to get a good grip with the water pump plier due to the position of the steam boiler. I might have to remove the whole thing.


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## MildredM (Feb 13, 2017)

Have you tried heating it up (not the machine! The part you are undoing).


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## catpuccino (Jan 5, 2019)

MildredM said:


> Have you tried heating it up (not the machine! The part you are undoing).


 Am waiting to hear back from either Paolo or the guys I've reached out to at Caffeine Fix (where the machine originally came from) about exactly which part unscrews before trying this* as I'm chewing up the nuts with my attempts.

* I'll probably get impatient after dinner and try it anyway.


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## catpuccino (Jan 5, 2019)

I'm tapping out. There's certainly something else at play here, probably thread locker like Dave suggests, can't move it at all with heat or anything. I'm going to reassemble, see if I can run some more descaler through it in case it is something that can be sorted out that way while I wait to hear back from @Paolo_Cortese and/or Caffeine Fix.


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## ajohn (Sep 23, 2017)

I think the usual threadlockers need 200C plus to degrade them. A heatgun can do it as can a cigarette type lighter if the flame is in the right place. Problem in this case is that parts that shouldn't get this hot may well do. Only way to localise heat is a fine propane flame but heat will spread rapidly anyway.

I'd assume they use a sealant suitable for drinking water but it doesn't need to have much strength really - more like the easy dismantle with hand tools type thread lockers. Trouble could still come by tightening too much while the stuff is still fluid.

I think Dave has mentioned over tightening before.

John

-


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## Border_all (Dec 19, 2019)

Out the box....

You may have heard of penetration fluid for cars thinking depending on what you have at hand cut a thumb off something like a kitchen glove pull over the joint use something similar to tierap or jubilee clip and spray penetration fluid in probably while machine on angle so you can tie off the other end for a few hours overnight. With luck the fluid will penetrate far enough so you can break the seal. I know this goes against the grain if you can not undo at all try a very minor tightening occasionally that can break a seal if that moves rock the nut backwards and forwards a few degrees before attempting to undo. Should that work and it commences getting stiff on undoing tighten a fraction and pop more penetration fluid in. Cycle gt85 car wd40 might work if you dont have penetration fluid. Good luck


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## DavecUK (Aug 6, 2013)

ajohn said:


> I think the usual threadlockers need 200C plus to degrade them. A heatgun can do it as can a cigarette type lighter if the flame is in the right place. Problem in this case is that parts that shouldn't get this hot may well do. Only way to localise heat is a fine propane flame but heat will spread rapidly anyway.
> 
> -


 No jesus christ don't do that, you will destroy the 1 way valve. They use a softer threadlock/sealant (Sigilent I think). Anyway, I am pretty sure it's probably the access and the difficulty of holding the thing without it twisting the mounting point. Although the steel is thick it's not intended to take huge force..


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## catpuccino (Jan 5, 2019)

Thanks all. In terms of time and energy I've got at the moment for this we're reaching the point I might look at how reasonable service costs are (I've asked Caffeine Fix this too..)...I think you're probably right re getting a good grip @DavecUK. Removing it would help, but here's the rub...I can't get the transducer off either to reach the mounting nut and it's impossible to get to from the other side. I'll have to remove the steam boiler to get to it when I open it up again.

I've reassembled and will try flushing again tomorrow evening as a hail mary.

FYI, here's a video of the flow return. Works as a cup warmer...


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## catpuccino (Jan 5, 2019)

p.s. humour me....if all else fails and an economic repair wasn't an option, why couldn't you just splice in an equivalent spec non-return valve in the piping just after the faulty valve...?


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## ajohn (Sep 23, 2017)

DavecUK said:


> No jesus christ don't do that, you will destroy the 1 way valve. They use a softer threadlock/sealant (Sigilent I think). Anyway, I am pretty sure it's probably the access and the difficulty of holding the thing without it twisting the mounting point. Although the steel is thick it's not intended to take huge force..


 I'd hope people were bright enough to realise that but replacing that as well might be the only option.

Looking at the first photo suspect I would try some double ended long hex keys to get the solenoid off and then a spanner on the fixing nut. The keys will have to be used the wrong way round so use an adjustable spanner on the short end. That will allow the unit to swing a bit allowing something to be used to grip elsewhere when the domed nut is removed. Once the whole unit is out dismantling the lot should be easier.

A set of long combination spanners might be a good idea and a pair of long pump pliers. Many are too short really. Buy the longest you can find. There are some cheap 400mm ones about maybe even longer. Make sure they have a curve etc and serrations in the jaws. Some makers have odd ideas about what the jaws should look like.

Maybe they should consider converting the fixing hole to a slot for maintenance as I would have thought various parts will need attention at some point. It looks like there is room for a couple of washers to get round using a slot.

Going back to the nut with an arrow in the photo it may be possible to get an open ended spanner on the flat on the elbow - then another on the lock nut - if it is one. Hopefully there is room to slacken it off a bit. Maybe impossible without getting the entire assembly out or at least swinging it out once the solenoid is removed.

John

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## catpuccino (Jan 5, 2019)

Since I had the machine reassembled I tried a longer more concentrated descale flush, with no results. Either the valve has failed or there's something stuck in it keeping it open, but I'm not convinced there's much scale worth talking about as everything's so clean.

I'll be disassembling again, I'll take out the steam boiler this time which should give enough access to remove the entire thing. Once I'm in the I'll replace the valve instead of cleaning unless the cause is something obvious like some debris.

Here's a video of the flow back through the valve, just for interest.


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## Border_all (Dec 19, 2019)

I wish you good luck ?


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## Border_all (Dec 19, 2019)

No idea if you have a part breakdown but i was looking and found this online might offer insight


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## ajohn (Sep 23, 2017)

Border_all said:


> I wish you good luck ?


 Me too but often as some one put the valve together it may be possible to take it apart and take a look.

Just to amuse DaveC - thank heavens I run a Sage.  Mainly mentioned as I was amazed how little sludge could stop a solenoid from working correctly. Just happened to be in the best place to do just that. It was easy to dismantle and clean - very easy.

John

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## catpuccino (Jan 5, 2019)

ajohn said:


> Me too but often as some one put the valve together it may be possible to take it apart and take a look.
> 
> Just to amuse DaveC - thank heavens I run a Sage.  Mainly mentioned as I was amazed how little sludge could stop a solenoid from working correctly. Just happened to be in the best place to do just that. It was easy to dismantle and clean - very easy.
> 
> ...


 Yeah in defence of the Vesuvius it seems very easy to work on *except* this damn manifold ? not one for tonight...tomorrow maybe. Always feel anxious until these things are sorted.


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## catpuccino (Jan 5, 2019)

Border_all said:


> No idea if you have a part breakdown but i was looking and found this online might offer insight
> 
> View attachment 35769


 That's a different Vesuvius ?


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## Border_all (Dec 19, 2019)

catpuccino said:


> That's a different Vesuvius ?


 Drat ?


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## catpuccino (Jan 5, 2019)

Does the steam boiler have a drain plug?


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## DavecUK (Aug 6, 2013)

Yes, but just disc the pipes, it will come out.


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## tohenk2 (Oct 11, 2017)

Thanks for sharing!

I don't need it (yet, fingers crossed) but I sure do want to know how you get it fixed.


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## catpuccino (Jan 5, 2019)

Back at this after being unwell for a few days.

With both boilers removed there's free access to the valve and I can now rotate it freely but there's not enough clearance to get it past the frame. I need to swing the manifold forward but I don't have a tool that'll fit around the brass nut with the clearance between that and the transducer and efforts to remove the transducer have not yet been successful.

Damned nuisance job.


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## cracked_bean (Apr 13, 2014)

Can you get the transducer off so a tool will fit?

Sent from my iPhone using Tapatalk


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## catpuccino (Jan 5, 2019)

cracked_bean said:


> Can you get the transducer off so a tool will fit?
> 
> Sent from my iPhone using Tapatalk


 As above was having trouble with it but just given it some brute force and it's off!

I'll need to replace all the thread locker I suppose...


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## DavecUK (Aug 6, 2013)

Have you actually removed the 1 way valve yet?

It's admirable that you have removed the Pressure transducer and Expansion valve (neither of which were your problem) and I would have tried hard not to remove them...really though the 1 way valves the gold standard for this repair after the whole unit is freed up by loosening the domed nut to the right of the transducer..

You will have to replace with PTFE tape...remember if it leaks it all has to come apart again so put enough PTFE on and do it right....It's why they use thread sealant on that part in the factory!!


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## catpuccino (Jan 5, 2019)

DavecUK said:


> Have you actually removed the 1 way valve yet?
> 
> It's admirable that you have removed the Pressure transducer and Expansion valve (neither of which were your problem) and I would have tried hard not to remove them...really though the 1 way valves the gold standard for this repair after the whole unit is freed up by loosening the domed nut to the right of the transducer..
> 
> You will have to replace with PTFE tape...remember if it leaks it all has to come apart again so put enough PTFE on and do it right....It's why they use thread sealant on that part in the factory!!


 It wasn't possible, or at least extremely tough, to get the 1 way valve out without swinging the entire manifold forward for more clearance. I found I wasn't able to get to the domed nut without removing the transducer, though I wanted to avoid doing so, it's done now. Bloody thread locker does a good job thuough.

So, here's where we are...


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## catpuccino (Jan 5, 2019)




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## catpuccino (Jan 5, 2019)

Looks clean to me....?


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## DavecUK (Aug 6, 2013)

Where is the rubber or silicone seal, is it the red bit remaining in the body?


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## catpuccino (Jan 5, 2019)

DavecUK said:


> Where is the rubber or silicone seal, is it the red bit remaining in the body?


 No seal, the red bit in the body is made of some metal and is not removable. For what it's worth the valve does seal, or at least it does against my attempts to pass water through it at low pressure.


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## DavecUK (Aug 6, 2013)

catpuccino said:


> No seal, the red but in the body is made of some metal and is not removable. For what it's worth the valve does seal, or at least it does against my attempts to pass water through it at low pressure.


 Really, that's interesting...I'd check with Paolo if I were you. I've not seen a metal to metal seal in a one way valve before?


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## DavecUK (Aug 6, 2013)

They normally look a bit like this...I think your O ring has gone somehow but what do I know??

http://coffeetime.wikidot.com/izzo-alex-anti-backflow-also-called-non-return-valve

Methinks you might need an O ring, perhaps this is why they sold it cheap?


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## catpuccino (Jan 5, 2019)

DavecUK said:


> They normally look a bit like this...I think your O ring has gone somehow but what do I know??
> 
> http://coffeetime.wikidot.com/izzo-alex-anti-backflow-also-called-non-return-valve


 What on earth....you're absolutely right. I wonder how that's come to be...fairly safe to assume that there should be an o ring since it's a water seal...


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## cracked_bean (Apr 13, 2014)

It definitely has the shoulder for an o ring!

Sent from my iPhone using Tapatalk


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## DavecUK (Aug 6, 2013)

catpuccino said:


> What on earth....you're absolutely right. I wonder how that's come to be...fairly safe to assume that there should be an o ring since it's a water seal...


 Pity you are so far away, I have a box of O rings we could have searched for one the right size. Just shows you how dishonest people are selling used stuff, cos that didn't just teleport out of there did it?

By a box of assorted edpm o rings from amazon and see if you can get one that fits.


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## DavecUK (Aug 6, 2013)

cracked_bean said:


> It definitely has the shoulder for an o ring!
> 
> Sent from my iPhone using Tapatalk


 Oh, for sure, I was just trying to be kind earlier, it's why I said I've never seen one without (metal to metal). Usually it's a rubber disk or more commonly an o ring. I doubt Paolo will know the size of the O ring, it's not a part that ever needs replacing, usually the whole valve is replaced after 15 or so years, or even longer.

measure it a bit and estimate the size required and then buy an assortment that covers that size and some around it.

https://www.amazon.co.uk/Fixman-362244-Assorted-Rubber-419-Piece/dp/B01MCRM3DO/ref=sr_1_6?keywords=o+ring+set&qid=1580587787&sr=8-6


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## DavecUK (Aug 6, 2013)

The o ring must be tight on the stem!


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## cracked_bean (Apr 13, 2014)

Might explain why it still partially works. Right now you are getting a metal-metal seal that is obviously not as good as rubber-metal! Interesting - I have been enjoying this thread because i get my V on Tuesday and it was almost ownership by proxy!


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## catpuccino (Jan 5, 2019)

DavecUK said:


> Pity you are so far away, I have a box of O rings we could have searched for one the right size. Just shows you how dishonest people are selling used stuff, cos that didn't just teleport out of there did it?
> 
> By a box of assorted edpm o rings from amazon and see if you can get one that fits.


 Indeed...I'll reserve judgement until I have a chat with him, previous owner ran a well regarded third wave cafe in the city and was quite charitable to me e.g. letting me have the machine several days before paying to check it over (pity I didn't spot this...) and refunded for the OEM steam arm. But as you say....it didn't just disappear of it's own accord.


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## catpuccino (Jan 5, 2019)

Now where did I put my callipers....?‍♂


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## DavecUK (Aug 6, 2013)

catpuccino said:


> Indeed...I'll reserve judgement until I have a chat with him, previous owner ran a well regarded third wave cafe in the city and was quite charitable to me e.g. letting me have the machine several days before paying to check it over (pity I didn't spot this...) and refunded for the OEM steam arm. But as you say....it didn't just disappear of it's own accord.


 Well unless you believe in teleportation, or interdimensional movement...or think it whizzed down the pipe and either got shredded by the gear pump or is stuck in there somewhere. My guess would be a cock up by the manufacturer of those commercial distribution units, as they come with the valve. The ACS factory would have fitted the complete unit and may not have spotted it on a power on heating pressure check.

I'll let Paolo know to check them in future, as if it's happened once, then it might happen again.


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## catpuccino (Jan 5, 2019)

DavecUK said:


> ...or think it whizzed down the pipe and either got shredded by the gear pump or is stuck in there somewhere


 That's nightmare territory.

I'll order some o-rings for tomorrow and hunt out my PTFE tape, hopefully get this all back together tomorrow!


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## catpuccino (Jan 5, 2019)

Looks like a 9mm ring, I'll buy a range though as you suggest Dave.

In terms of was it an error upstream in production, all I can say is before I got there the insides showed absolutely no signs of being worked on. Unless they were meticulous in no leaving marks on nuts etc, I find it hard to believe it's been serviced down to the valve before. Also, what we presume is the original thread lock is there of course.


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## catpuccino (Jan 5, 2019)

Edit: Nope ignore this post


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## catpuccino (Jan 5, 2019)

DavecUK said:


> measure it a bit and estimate the size required and then buy an assortment that covers that size and some around it.
> 
> https://www.amazon.co.uk/Fixman-362244-Assorted-Rubber-419-Piece/dp/B01MCRM3DO/ref=sr_1_6?keywords=o+ring+set&qid=1580587787&sr=8-6


 Seems those assorted packs all go up to 2mm width after 5-6mm diameter, needs a 9x1. I've ordered a 7mm(inner)9mm(outer)x1 diameter o-ring from Amazon for tomorrow as that's the closest they have for delivery tomorrow, undersizing would ensure a tight fit - and if it's a no go there's a 9x1 which can arrive for Monday.


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## DavecUK (Aug 6, 2013)

This is the specification, material is NBR

Ø8.9 X Ø1.9 X Ø12.7 NBR 70 SH


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## catpuccino (Jan 5, 2019)

DavecUK said:


> This is the specification, material is NBR
> 
> Ø8.9 X Ø1.9 X Ø12.7 NBR 70 SH
> 
> View attachment 35907


 Ah wonderful. Mind linking where that diagram comes from just for posterity?


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## DavecUK (Aug 6, 2013)

Diagram comes from me, it's confidential so you only have part of it. The bit you need.

I think Paolo will also send you an O ring, once he has your details, but it might take a while!

P.S. I was right, the whole distributor comes with the 1 way valve pre assembled from the manufacturer, so they must have fecked up. Paolo never opens them to check for obvious reasons. Well done on your disassembly job.


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## catpuccino (Jan 5, 2019)

DavecUK said:


> Diagram comes from me, it's confidential so you only have part of it. The bit you need.


 I see. Ta very much, sourced a good nitrile match, on it's way tomorrow.


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## DavecUK (Aug 6, 2013)

OK it should work fine....I forgot I actually had the diagram. I also let Paolo know, because obviously it's not a specific check they ever make.

This is the reason why I tend to get given prototype machines to feed back on.....I tend to spot all the little things, problems and issues that people miss. Some companies hate me, others love me.


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## catpuccino (Jan 5, 2019)

Much better. Hope to get some time later to put it all back together and test for leaks. Need to scrape off the old thread lock first.


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## DavecUK (Aug 6, 2013)

Well done...


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## catpuccino (Jan 5, 2019)

Frustratingly, project paused for the night...even with generous PTFE tape to try and shim it, the 90 degree joint attached to the non return valve will not tighten so it's 90 degrees downwards thus can't attach the pipe without pinching it. It wants to tighten about 120 degrees further (i.e. facing into front of the machine).

I guess they used the thread lock glue to fix the joint printing down at the factory?


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## cracked_bean (Apr 13, 2014)

Is it a single thread start, I assume it will be but can't help asking?

Is there any way to leak test it at the right angle but not fully tight, the tape should give you some seal?

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## catpuccino (Jan 5, 2019)

cracked_bean said:


> Is it a single thread start, I assume it will be but can't help asking?
> 
> Is there any way to leak test it at the right angle but not fully tight, the tape should give you some seal?
> 
> Sent from my iPhone using Tapatalk


 It is yes. It doesn't tighten anywhere near right enough for it to be worth testing I'm afraid.

I'll get some loctite tomorrow.


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## cracked_bean (Apr 13, 2014)

With thread locker loctite surface curing is quick but if there is any amount of thickness best give it a long time. Fingers crossed.

Sent from my iPhone using Tapatalk


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## DavecUK (Aug 6, 2013)

With the right amount of ptfe tape things don't have to be fully tight.


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## catpuccino (Jan 5, 2019)

DavecUK said:


> With the right amount of ptfe tape things don't have to be fully tight.


 That was what I was aiming for but even with a significant amount it was 'finger loose' at the right angle.


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## DavecUK (Aug 6, 2013)

What was a significant amount?


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## catpuccino (Jan 5, 2019)

DavecUK said:


> What was a significant amount?


 Did several attempts typical 10-15 wraps up to many more than that....out of frustration I just did a very large number (60+?) and I think I'm pretty happy with the tightness, enough to give it a go anyway. The joints don't meet as before but seems quite a sufficient seal.

The PFTE I have is quite thin unfortunately, I suspect I could take what I'd think of as reasonable and 2x it.


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## DavecUK (Aug 6, 2013)

When I use PTFE I put enough on so that I can just need to use a spanner, it's slightly too much to tighten past the first turn with fingers. As long as I have a decent number of thread engaged, I'm happy. So a thermal probe I will screw in, but not necessarily all the way down as it does nothing more after a few turns.


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## catpuccino (Jan 5, 2019)

Well I'm delighted to say that after initial testing the problem is now completely solved.

Pressure appears to be being controlled properly right at the start of the shot, no water rolling back through the tank feed tube and no initial temperature drop between shots.

I'll continue to monitor for any leaks from the resealed joints over the coming days. I'll post some notes on the repair later and just clean up what was going on here as it might prove useful to someone debugging their Vesuvius in the future.

Cam in desperate need of a lube now though ?


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## catpuccino (Jan 5, 2019)

edit: posted too soon...ignore for now.


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## catpuccino (Jan 5, 2019)

Now that this is solved, a brief write-up of the problem and fix for future Googlers since the thread's a little messy:

A big thanks to @DavecUK who started this with me over on the ACS owners forum where I'll also post this summary shortly.

*Background*

Machine new to me, somewhat known history. Machine was used for back to back shots during a few events by a local cafe, this masked the problem which requires the machine to idle for a bit before becoming problematic.

*Symptoms*



Water taking several seconds to flow through shower head for walk up shots, or when machine left idle for several minutes. Behaves as normal when pulling back to back shots.


Significant initial boiler temperature drop on first shot after idle (down to 75-80c).


Water (warm) flowing back into the tank through the tank feed tube.


Thermosyphon stall (sometimes)


Sound of water hitting hot exposed element in brew boiler after it has drained and been exposed.


*Diagnosis*

Problem with non-return valve in the water distribution manifold behind the group head (see post #1). Possibly stuck open with scale or debris but machine shows no other signs of scale.

*Repair*

The Vesuvius has a lot of room to work in and my takeaway is that of the mechanical components in the machine this is basically the only difficult thing to access. The inside has a few unfinished edges as you'd expect, be careful not to cut yourself as many times as I did...

Both steam and brew boilers need to be removed to provide unobstructed access to the valve area. All connections to the water distribution manifold are sealed with thread lock (it looks blue-ish to me, possibly regular strength Locktite). They can be removed with ordinary hand tools but require more force than can be applied with the manifold situated in the body.

You'll likely need to remove the pressure transducer to access the nut that frees the manifold. It'll be tight, but it can be done.

Once removed, clean/repair the non-return valve (in my case the rubber o-ring was missing causing it not to seal properly) and replace all connections with appropriate seal (e.g. PTFE tape, thread lock or similar. I used PTFE, if I were to do it again I'd use Locktite 55 to reposition the angle joint easier).


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## mctrials23 (May 8, 2017)

So I assume this had been as issue since new? Had none of the previous owners noticed this or do you think one of them gave up and sold it on as it wouldn't appear to have issues until you had used it a bit.


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## DavecUK (Aug 6, 2013)

mctrials23 said:


> So I assume this had been as issue since new? Had none of the previous owners noticed this or do you think one of them gave up and sold it on as it wouldn't appear to have issues until you had used it a bit.


 I'll leave him to answer that but will point out that the Vesuvius brew boiler design is such that a problem like this is not so easily noticed by people who might use the machine a lot and not be alive to a situation when something seems "not quite right". This would be true for many owners. I said once that I could probably diagnose minor faults in a high % of 3+ year old machines where owners think they don't have any problems at all. Many of those I would tell in under 5 minutes from "little signs" of a problem.

With the V the brew boiler design really is the "Gold Standard" as it is in the Duetto (for obvious reasons). However the modern crop of Stainless steel boiler machines tend to use a top and bottom thermosyphon feed design because it's cheaper and easier than welding fittings on the side of the steel boiler! This means that design considerations ideally need to be taken and they are in the Minima for example. Some companies try and tilt the brew boiler (sort of helps but not so much).

However the gold standard of design, side exit thermosyphon top and lower third can fool the unwary. The thermosyphon rarely airlocks so no cold group and often quite a time can go by with a faulty anti-backflow valve. So people think nothing is wrong...left long enough the top of the heating element can become exposed, although by then the group would be stone cold. If the machine is left unattended all day with a fault like this though it can happen. As it can in any machine with a faulty 1 way valve.

It's why I have this "thing" about *really clean water* and if a group in any machine goes cold or only hot warm when it's on (it's a warning sign), as is a quick rush of the pump filling a void in the boiler and then the normal rush of the pump against the back pressure of the gicleur as it fills the headspace in the portafilter, or the long pause before water runs from an open shower screen.!


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## catpuccino (Jan 5, 2019)

mctrials23 said:


> So I assume this had been as issue since new? Had none of the previous owners noticed this or do you think one of them gave up and sold it on as it wouldn't appear to have issues until you had used it a bit.


 The machine had 1 previous owner which was a local third wave specialty cafe that used it for a few events. They closed down and the owner moved out of the area hence the quick and cheap sale. My belief is that given how they were using it, as Dave describes, it just wasn't apparent to them. When I got hold of it and started using it enthusiastically, I didn't notice it either as the machine has to idle for some time before it becomes obvious. It was only when I started returning to the machine after being idle for an hour or two that I became aware of the issue, and subsequently once aware could spot the lesser symptoms after idling for shorter periods.


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## catpuccino (Jan 5, 2019)

DavecUK said:


> However the gold standard of design, side exit thermosyphon top and lower third can fool the unwary. The thermosyphon rarely airlocks so no cold group and often quite a time can go by with a faulty anti-backflow valve. So people think nothing is wrong...left long enough the top of the heating element can become exposed, although by then the group would be stone cold. If the machine is left unattended all day with a fault like this though it can happen. As it can in any machine with a faulty 1 way valve.


 I read while researching around the issue that faulty non-return valves can go unnoticed on plumbed in machines because the line pressure stalls the backward flow. Not true for the Vesuvius of course but interesting nonetheless.


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## Nikko (Aug 20, 2014)

Why is it not true for the Vesuvius?


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## cracked_bean (Apr 13, 2014)

It doesn't take line pressure. It just fills it's internal tank from the water.

Sent from my iPhone using Tapatalk


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## Nikko (Aug 20, 2014)

cracked_bean said:


> It doesn't take line pressure. It just fills it's internal tank from the water.
> 
> Sent from my iPhone using Tapatalk


 Thank you.


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## mctrials23 (May 8, 2017)

Thanks for clearing that up. I wasn't suggesting that the pervious owner was dishonest, it just sounded like an issue that could easily be passed on without the new owner realising until long enough had passed that the old owner could claim it was fine when it left them. I have come across plenty of people who would be happy to move something on with known issues because they were hard to notice at first.


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## catpuccino (Jan 5, 2019)

mctrials23 said:


> Thanks for clearing that up. I wasn't suggesting that the pervious owner was dishonest, it just sounded like an issue that could easily be passed on without the new owner realising until long enough had passed that the old owner could claim it was fine when it left them. I have come across plenty of people who would be happy to move something on with known issues because they were hard to notice at first.


 Yep that's how I read it no worries.


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## DavecUK (Aug 6, 2013)

catpuccino said:


> I read while researching around the issue that faulty non-return valves can go unnoticed on plumbed in machines because the line pressure stalls the backward flow. Not true for the Vesuvius of course but interesting nonetheless.


 That's right, on machines that plumb the cold water directly into the brew system the pressure often hides the problem until they move to tanked operation because the back pressure within the boiler is much less than the pressure in the boiler. As you say not true on the Vesuvius or any well designed pressure profiler that can be plumbed in for obvious reasons.


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