La Pavoni Millenium, Help with water leak

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Flounder

#1: Post by Flounder »

Greetings, I have recently noticed that just before my machine is up to pressure, water starts dripping from the shower head. It looks like at least an once and won't stop until I pull the lever all the way up and push it back down. I maybe have pulled 30 shots since a full seal kit was installed. Worked perfectly up until 2 days ago. Any clues what might be going on? Thanks

mwynne

#2: Post by mwynne »

Brass or plastic grouphead sleeve?

I recently had something similar with my machine (plastic sleeve). I pulled and cleaned the grouphead sleeve and installed a new sleeve o-ring. I didn't need to teflon tape the threads, but have heard that may help as well.

ojt

#3: Post by ojt »

Yeah the suspects would be the grouphead gaskets, perhaps a damaged plastic piston, badly installed PF/showerscreen gasket...

Also do you have the piston pressure kit? If so the leak could originate from there, between the shaft and the piston.
Osku

Flounder

#4: Post by Flounder »

Thanks for the replies. It is a plastic piston and sleeve. I don't know what a "piston pressure kit" is. I replaced all the seals and new plastic sleeve less than 30 shots ago. I don't think it's the shower screen gasket as it leaks out through the shower screen holes. A few days ago while trying to dial in a new bean I almost choked a shot that took quite a bit more pressure so I slowed down the speed on the lever , the shot was pretty good. Could that have possibly blown a piston gasket? Even if the piston gasket is bad, why would water be able to get to the piston when the lever is in the down position? Today I filled it with water to about 3/4" from the top of the sight glass, turned the machine on, water started to drip just before it was up to temp. and continued for about 5 minutes then stopped , putting out a total of 4 oz. I guess I will open it up this weekend and have a look. Until then it's Hario v60
time.

wkmok1

#5: Post by wkmok1 »

Try smearing a light layer of Dow 111 onto the piston gaskets and the inner surface of the sleeve. I do this when mine starts dripping. But I only get a spoonful of water though.

Also make sure the piston gaskets are pointing the right way. The top one points like a 'u' and the bottom one like an 'n'.
Winston

Flounder

#6: Post by Flounder »

So I just pulled the piston out, the piston seals and sleeve all look perfect. The piston had loosened from the shaft, not sure how much, in retrospect I would have tightened it and counted the revolutions to know. Instead I just spun it off. I applied a thicker wrap of teflon tape and an uncomfortably harder torque than before. Uncomfortable in that a stainless steel shaft being threaded into plastic can go wrong pretty quickly. Reinstalled everything carefully with 111 grease and still drips the same way. I am trying to understand what else this could be? In this diagram....
http://www.linz.wright.name/pavoni/Pavo ... ection.png
I see no way for this to be happening unless 1-the piston seals are bad. They look and feel new and cause friction to be felt at the lever.
Or 2-the sleeve seal is bad which I find highly unlikely as this seal was replaced recently and makes no contact with moving parts. Way too much water is dripping which tells me something should be glaringly obvious inside the group head. I will pull the sleeve out tomorrow and look at that seal.
When upgrading to a brass piston do you also replace the plastic sleeve? Any good sources for those? Thanks again for co pondering this conundrum.

wkmok1

#7: Post by wkmok1 »

Hmmm... Might as well buy a brass piston. They last forever. It's just a matter of time for the plastic one to fail.

Can you feel around the inner surface of the sleeve to see if you can feel any cracks? Long shot. If there is a crack, you would not expect the leak to stop when you pump the lever. Ditto for the case of the O-ring outside the sleeve being bad. With that much water coming out, you may be able to see the source, through the holes of the shower screen vs its outside circumference.
Winston

Flounder

#8: Post by Flounder »

Thank you everyone for the help. I pulled of the shower screen to see where the water was dripping from and it was coming from the outside of the sleeve, so I pulled the sleeve out to check the O ring, It looked fine but was obviously not making a tight seal. I wrapped teflon tape around the sleeve threads and also inside the O ring groove to give it a tighter fit. That's all it took. I wonder if that O ring was not the proper one? I will pull some shots in the morning. Cheers

ojt

#9: Post by ojt »

Other option is that the sleeve was not screwed in enough. When installing the stainless steel sleeve I noticed it was not super easy to screw in completely. Just a thought.. Of course adding teflon tape or perhaps some thread lock or something would help. In the end I didn't need anything with the stainless steel after I got it inserted far enough.
Osku

User avatar
guijan12

#10: Post by guijan12 »

Flounder wrote:Thank you everyone for the help. I pulled of the shower screen to see where the water was dripping from and it was coming from the outside of the sleeve, so I pulled the sleeve out to check the O ring, It looked fine but was obviously not making a tight seal. I wrapped teflon tape around the sleeve threads and also inside the O ring groove to give it a tighter fit. That's all it took. I wonder if that O ring was not the proper one? I will pull some shots in the morning. Cheers
That bought you time to go for the final solution: the brass piston and stainless sleeve. :D
Regards,

Guido