Leaky La Pavoni Millenium group.

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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Kaffee Bitte
Posts: 673
Joined: 17 years ago

#1: Post by Kaffee Bitte »

My La Pavoni Millenium (stradivari 16 cup) has a pretty serious leak from the group head after it is warmed up. Now every time in the past when this has happened all it needed was a new piston sleeve O-ring. Which I just replaced yesterday and put the group back together. And this morning it warms up and starts doing this again. I have changed the o ring out and the piston sleeve numerous times now in the seven years I have had this machine. Never once has the problem not been fixed by the swap out.

Anyone have an idea what might be going on here this time as I am stumped. I should add that when I pulled the group I gave the sleeve a good cleanup and checked it for any cracks as they do crack sometimes. It didn't have any that were visible. And I used the tool I got from Stefano's espresso care to remove and replace the group.
Lynn G.
LMWDP # 110
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rpavlis
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Joined: 12 years ago

#2: Post by rpavlis »

Are you sure that the dimensions of the sleeve have not changed over time? How old is this machine? Do you use it a lot?

Is the leaking around the piston or around the sleeve? These polyphenyl sulphide components are subjected to severe forces whilst above their glass temperature. (~85C) Although PSS is regarded as a material that can stand high temperatures, there is a limit to its strength.

I would measure the inside diameter of the sleeve with an inside micrometer in many locations and in several directions.

You really should not be needing to replace the piston seals very often. The fact that you seem to have to do this often implies also creep of the PSS part so that its dimensions have slowly changed in time.

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drgary
Team HB
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#3: Post by drgary »

If the cylinder has expanded sometimes wrapping PTFE tape under the piston seals to shim them will allow them to function normally without more expensive repairs.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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rpavlis
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Joined: 12 years ago

#4: Post by rpavlis »

A replacement polyphenylsulphide sleeve for these machines is not especially expensive. OE has them for US$22.50 or something like that. It is still my opinion that you should check the diameter of the present sleeve and proceed on the basis of what you find when you do that.

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Kaffee Bitte (original poster)
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Joined: 17 years ago

#5: Post by Kaffee Bitte (original poster) »

I have replaced the o-ring about 8 times I believe, so about once a year since I got it 7 years ago. The sleeve I have replaced twice. Both times I had to replace it because I cracked it trying to get it out to replace gaskets or clean the group. This shouldn't have been the issue this time since I bought the little $1.50 tool to remove it after the last time it happened. I went ahead and bought a new sleeve due to the low price point and am now just waiting for it to arrive by snail mail. Hopefully this change out solves the issue as I have been without espresso for four days. Something that has rarely happened in the 7 years since I bought this machine. I use it daily, usually just in the morning, but also in the afternoon or evening on occasion. I have kept up on regular maintenance for it, replacing parts, lubing, and cleaning pretty fastidiously.
Lynn G.
LMWDP # 110
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Kaffee Bitte (original poster)
Posts: 673
Joined: 17 years ago

#6: Post by Kaffee Bitte (original poster) »

Well It is a good thing I ordered a replacement sleeve. When I replaced the old one this time I cracked it. So new sleeve went in and problem solved. Note to self on next group cleaning, be more gentle on returning sleeve to group.
Lynn G.
LMWDP # 110
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