Need advice on replacing La Marzocco Linea Mini vacuum breaker

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

#1: Post by PandaSPUR »

The vacuum breaker on my La Marzocco Linea Mini recently failed (after over 3 years of use) and I found the various threads on this forum talking about it.

I ordered a replacement part which finally arrived today and proceeded to try replacing it. Took off the top panel, left the sides on for now.

I was able to get a wrench on the existing valve and I started to turn, when I noticed that instead of the valve turning on its socket, the entire elbow was starting to bend...

Here's a picture to demonstrate what I'm talking about. The circled area started to bend when I tried to loosen the valve (by turning counter clockwise).



At this point, I immediately stopped and used my hand to kind of nudge it back. Machine seems to be working fine still, no leaks at that elbow, but vacuum breaker still not fixed obviously.

My question now is, how am I supposed to properly unscrew this valve without damaging it? It looks like I could hold the bottom half in place with a second wrench while I unscrew the top piece, but even that seems risky.

I'd rather not have to pay for a professional house call.. but sigh maybe I have to?

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civ

#2: Post by civ »

Hello:
PandaSPUR wrote: ... vacuum breaker on my La Marzocco Linea Mini recently failed ...
... ordered a replacement part ...
I'd say a good clean-up and a new seal would have sufficed, but ...
PandaSPUR wrote: ... a wrench on the existing valve and I started to turn ...
Bound to happen.
From what I can make out of the photograph, that is not how it is done, unless you want to bend it badly.
PandaSPUR wrote: ... how am I supposed to properly unscrew this valve ...
It would seem that what has to be undone is is not the valve but the nut at the other end of the copper tubing that bent under the torsion force you applied to the valve body.

Once undone, you can work on the dissassembly without major issues.

Best,

CIV

yertchuk
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#3: Post by yertchuk »

Maybe another option would be a socket with a T-handle? That way, you would only be applying torque to the breaker, without a bending moment to the horizontal pipe. I'm not sure if there's enough length exposed above the plastic pipe fitting, though.

For reference, a T-handle looks like this: https://tinyurl.com/2mxj5n9f

I'll be following your progress, since at some point I'm sure I'll have to do this on my LMLM.

-Peter

tglodjo

#4: Post by tglodjo »

Remove the plastic tube and only remove/unscrew the top piece. You can use a wrench to hold the bottom half stable while you unscrew the top, which should prevent bending the elbow. It's been a year or so since I last did this, but I remember using two wrenches--one for torque and the other for stability.

PandaSPUR (original poster)

#5: Post by PandaSPUR (original poster) »

civ wrote:Hello:

I'd say a good clean-up and a new seal would have sufficed, but ...


Bound to happen.
From what I can make out of the photograph, that is not how it is done, unless you want to bend it badly.


It would seem that what has to be undone is is not the valve but the nut at the other end of the copper tubing that bent under the torsion force you applied to the valve body.

Once undone, you can work on the dissassembly without major issues.

Best,

CIV
I figured if I was going to take it apart, I'd rather just replace the whole valve to prolong the amount of time before I had to do this again. But I also couldn't find a place to get just the pieces that go inside the valve.

I thought about removing that entire piece from the steam boiler first, but I'd have to look more into that part of the connection to make sure I can put it back together properly. It looks like the crush washer on that end might be a different size than the one used directly under the breaker valve.
yertchuk wrote:Maybe another option would be a socket with a T-handle? That way, you would only be applying torque to the breaker, without a bending moment to the horizontal pipe. I'm not sure if there's enough length exposed above the plastic pipe fitting, though.

For reference, a T-handle looks like this: https://tinyurl.com/2mxj5n9f

I'll be following your progress, since at some point I'm sure I'll have to do this on my LMLM.

-Peter
I thought about this but that copper pipe bent surprisingly easy so I'm not sure if this would be enough.
tglodjo wrote:Remove the plastic tube and only remove/unscrew the top piece. You can use a wrench to hold the bottom half stable while you unscrew the top, which should prevent bending the elbow. It's been a year or so since I last did this, but I remember using two wrenches--one for torque and the other for stability.
I've got an extra channel-lock wrench I could use to hold the bottom steady. You think that should be enough?
Also, is removing the side panels as easy as taking off the 4 flat head screws on the front of the machine or am I missing something.

PandaSPUR (original poster)

#6: Post by PandaSPUR (original poster) »

ALRIGHT! GOOD NEWS.

Managed to get it done and everything seems to be working just fine.

I decided to try getting a wrench on the bottom half without removing the sides first.


I seemed to get decent leverage on the bottom, so I proceeded very carefully and the top half of the valve came off first. Then the second.

The new valve seems different compared to the old one (which is already different than some of the bell shaped ones I've seen posted before).
A bit taller, and the connection for the silicone tube is slightly different. I could not manage to pop the new one open to get a look inside.


Next, an issue that I did anticipate... The new valve did not point back towards the steam boiler at the same angle once put on.
This is how it looked when just finger tight:


This is how far I could get it before I gave up:


Luckily this was good enough, although I did have to re-route the silicone tubing. I'll have to think about how to optimize this to try and have it touching as few other hot parts as possible, but the tubing should be fine.

tglodjo

#7: Post by tglodjo »

Congrats on getting everything switched out. Looks great. I remember the line for the plastic tubing orienting in a different direction too. Also glad you figured out that you shouldn't need to remove the side panels. LM Home told me that a vacuum breaker seal could need replacement up to every 6 months as part of regular maintenance, so only having to remove the top panel is important for ease and accessibility. (That said, I've only had to replace it twice in 5 years of ownership.)

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civ

#8: Post by civ »

Hello:
tglodjo wrote: ... a vacuum breaker could need replacement up to every 6 months ...
Hmm ..
Vacuum breaker or vacuum breaker seal?

When a vacuum breaker fails, it is a problem with the seal.
The problem is caused by mineral deposits, the gasket/'o'ring material degrading or a confuence of both.
But it is not a problem with the vacuum breaker itself.

I'll defer this to HB member Paul Pratt of espressorestorations and what he has to say about vacuum breakers:

http://www.espresso-restorations.com/va ... akers.html
O-rings revisited Feb 05

Early December 2004 I started a small experiment. I replaced the o-rings on a number of units around HK and used
different types of o-rings to see how each one held-up.

All the machines were on 24/7 since December and yesterday I went around an inspected them all. The Viton
o-rings had hardened and were barely making a seal. So they only lasted about 60 days before they almost failed.
The silicone rubber ones were still soft and making excellent seals.

The silicone o-rings cost me 6 times as much as the viton but I wouldn't recommend the viton o-rings to anyone.
As you can see, he does not go around HK replacing vacuum breaker valves, he replaces 'o' rings and seals.

Best,

CIV

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Shawnaks5
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#9: Post by Shawnaks5 »

Glad you got it fixed! I think the Vac Breaker is one of the most irritating things about the LMLM. With that said, I started leaving my machine on all the time and it has extended the life of my Vac Breaker.

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Shawnaks5
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#10: Post by Shawnaks5 »

civ wrote:Hello:

Hmm ..
Vacuum breaker or vacuum breaker seal?

When a vacuum breaker fails, it is a problem with the seal.
The problem is caused by mineral deposits, the gasket/'o'ring material degrading or a confuence of both.
But it is not a problem with the vacuum breaker itself.

I'll defer this to HB member Paul Pratt of espressorestorations and what he has to say about vacuum breakers:

http://www.espresso-restorations.com/va ... akers.html



As you can see, he does not go around HK replacing vacuum breaker valves, he replaces 'o' rings and seals.

Best,

CIV
I agree with this as well! I actually added a small coat of food safe grease to my Vac Breaker seal. Maybe that's another thing that's helping me along with leaving the machine on.