ECM Technika IV steam wand design question

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
rustyfence

#1: Post by rustyfence »

I'm in the middle of renovating an older ECM Technika IV. I have a leak at the top of the steam wand assembly I'm trying to fix, but the design has me stumped!

For this model, the main lower nut (28) tightens against a lock nut (7) on the threaded valve body (6). In between them is a teflon gasket (8). The gasket does stop steam leaking out between the two nuts, but there is no seal of any kind *above* the lock nut (7). Unsurprisingly, when I turn on the steam I get leaking straight out the top of the lock nut! The steam seems to be travelling from inside the assembly, through the thread, and exits at the top.

I can't fix it until I understand how this is actually supposed to seal!

What am I missing here? The only things I can think of are -
  • Is the seal between the ball and socket (11) supposed to be perfect so that there should never be steam leaking to the outside of (11)?
  • Or is the teflon gasket (8) supposed to somehow additionally crimp against the thread (6) so as to prevent steam travelling upwards through the thread?
  • Or am I supposed to be applying a thread sealant to the lock nut (7)?
None of these seem very likely or very satisfactory :? Any insight would be appreciated!


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rustyfence (original poster)

#2: Post by rustyfence (original poster) »

No ideas anybody? If I can't figure out how this is supposed to seal, I'll probably need to make do with some teflon tape or thread sealant....

Brewman

#3: Post by Brewman »

Hmm sort of hard to tell just from watching the drawing and not seeing the actual parts. My ecm classika has a simular design, noticed the bolt that held the steam wand ball joint in place was not tightened too hard when taking my steam wand apart, so I'm assuming the spring in there is supposed to push hard enough onto the ball to seal or at least seal most of it and in your case gasket 8 would seal the rest I guess?

Here's how my classika wand looks pg 9
https://wiki.wholelattelove.com/images/ ... _Parts.pdf

ira
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#4: Post by ira »

Looks like 10 and 11 should seal to the inside of that fitting and the nuts should never see steam. Maybe the washer is just there to make it easy to work on.

Ira

rustyfence (original poster)

#5: Post by rustyfence (original poster) »

Thanks ira and brewman. Looks like I should concentrate on getting a better seal between (11) and the ball. This is a metal-on-metal interface, with the "ball pan" (11), as ECM call it, being brass, and the ball head being stainless steel. I already gave the ball pan socket a very light sand with fine wet and dry, but looks like I'll have to match the profile to the ball better ... or buy a new (11).

ira
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#6: Post by ira »

28 is a gasket that should probably prevent metal on metal contact and seal the gap.

Ira

rustyfence (original poster)

#7: Post by rustyfence (original poster) »

An update.

So I worked on getting a better fit between the ball and socket. I did this by putting the "ball pan" in a drill chuck, applying a little fine polishing compound, and spinning the ball pan seat over the ball. The profile of the pan and ball are now as close as they're ever going to get.

Unfortunately, even with those pieces fitting very well, there's still a leak out into the ring nut. Being a simple, single metal-metal contact, I think now there will always be some leakage there.

I'm now moving towards the theory that they used a thread sealant in manufacture. I have seen thread sealant used in other fittings on the ECM technika (e.g. on boiler fittings) so it is possible that the factory used sealant here as well.

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Brewman

#8: Post by Brewman »

Hmm mayby if it's an older unit - the spring has gotten weak from sitting in there and provides insufficient pressure to properly seal between the two surfaces? But yes they may have used some sealant I saw some in the threads when I took my classika wand apart, but in the actual wand not the nuts holding it in place.

rustyfence (original poster)

#9: Post by rustyfence (original poster) »

Thank you for that info. What I might do is disassemble the hot-water tap asssembly and carefully check for sealant there.

I don't think it's a spring issue on the steam wand side - it's plenty strong. So strong in fact that I need to add extra weight to hold the machine down when I am screwing the spring assembly back in, otherwise the machine will lift off the table.

ira
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#10: Post by ira »

ira wrote:28 is a gasket that should probably prevent metal on metal contact and seal the gap.
My bad it's 29, but I still think there should be a gasket between the 2 metal parts, do you have part 29?

Ira