Europiccola blowing bubbles

[roadman]

First off I just want to say it's delightful to have found a forum for lever machines. What a great idea!

I was recently gifted with my first ever espresso machine, a used pre-Millennium La Pavoni Europiccola. It was leaky so I replaced the seals on the group and the steam shaft. So far so good. It worked well through about 3 - 4 months of light use... until now.

Now about midway into the pull my nice steady stream of espresso turns into a ribbon of bubbles. There is a post with pictures about this on CG, though after reading it I'm still not sure how to correct the problem. http://www.coffeegeek.com/forums/...o/questions/165652

Anyone have a clue about what's going on here?

I'm using fresh beans from different roasters, I'm tamping and dosing properly and I have a good grinder.

Could there be a problem with the seals? It seems a little early for seals to be failing, but who knows, I may have unduly stressed the seals while I was on the steep part of the La Pavoni lever learning curve.

Jon

[Kaarina]

Hi,
I have a rather new Europiccola and I get this every time. I haven't minded much, since I have had other challenges to concentrate on - like first getting no decent crema, then not getting decent microfoam - I have just snagged the cup away and let the foam go to the tray.
One idea - why don't you go to the Pavoni website and send them an email? I got an answer to one of my queries - albeit with a couple of weeks delay.
I would also love to hear if there is something to be done about this foam. If not, then we have to take a Gallic attitude
best regards Kaarina

[Paul L]

Since I started home roasting I get this amazing looking liquid flowing through the pf, the darkest most striped crema I have ever seen right the way through the short shot that a Pavoni double basket produces. Wonderful. However, at the end of the shot I also get the larger bubbles. I have read that it is a feature of fresh coffee which has not degassed enough although I am still finding this on 5-day old roast and so I don't know, it's too early for me to tell. I know I read somewhere that the pressure profile of a Pavoni pull is that it achieves the required 9-bar through the shot until that last bit when the preesure drops to 7-bar. Basically the part where we see the bubble. Perhaps there is a connection.

[luthier]

Maybe some manual pre-infusion (push the lever up and down for a few times) will help?

[srobinson]

Jon, let me give this a shot. From reading your post, it looks like you replaced the gaskets...everything was looking fine and this has only started recently. Symptoms are very close to what I ran into the first time I took my Pavoni apart. What I think is happening is this:

1) When you replaced your piston gaskets you might not have screwed the piston back on the shaft tightly.
2) If not, then over time it will slowly unscrew and the piston will start to partially block the water inlet hole
3) As such you may not be getting a full amount of water in the grouphead thus
4) you will have a soft pull at the top of your stroke and you will be pulling some air at the end of each shot.

I would suggest that you take your grouphead off and pull the piston to make sure it is very tight on the shaft. If everything is proper then you should hear close to a click at the top when the water fully rushes in. You should have a firm pull from the start.

I would give this a look before I start chasing some of the suggestions that I saw on the CG thread.


Let me know if this works

[srobinson]

Jon, let me give this a shot. From reading your post, it looks like you replaced the gaskets...everything was looking fine and this has only started recently. Symptoms are very close to what I ran into the first time I took my Pavoni apart. What I think is happening is this:

1) When you replaced your piston gaskets you might not have screwed the piston back on the shaft tightly.
2) If not, then over time it will slowly unscrew and the piston will start to paritally block the water inlet hole
3) As such you may not be getting a full amount of water in the grouphead thus
4) you will have a soft pull at the top of your stroke and you will be pulling some air at the end of each shot.

I would suggest that you take your grouphead off and pull the piston to make sure it is very tight on the shaft. If everything is proper then you should hear close to a click at the top when the water fully rushes in. You sqhould have a firm pull from the start.

I would give this a look before I start chasing some of the suggestions that I saw on the CG thread.


Let me know if this works

[roadman]

Thanks for your replies.

It's been one of those days. First thing in the morning, the bristles started dropping out of the brush I use to clean the group. Next the toaster went belly up. Then the stereo. Looks like the beginning of a full scale appliance revolt, but I press on.

Steve suggested I check the piston on the Pavoni. Sounded plausible. To be thorough I decided to de-scale the machine before opening it up. Used vinegar. Now it acts like the seals are truly shot - no pressure, zip, nada. Took apart the group.

Aha! Didn't know it but the retaining ring in there was starting to rust through, the vinegar pushed it over the edge and it snapped. Figured this was the problem. Happily headed out to the auto parts store for a spare, came home and installed the new ring. Put it back together and zip, no pressure again.

Now I'm waiting for a new set of seals to come in. I will post an update after the seals are replaced. Hopefully at the end of all this the bubbles will be gone.

Jon

Ps to Steve - the piston and the shaft were tight, my guess at this point is that the seals were just starting to go. When I first got the machine I choked it fairly often by using too fine a grind. Unfortunately I also continued to force the lever down even though it was locked up. I'm guessing this has been pretty tough on the seals. Probably won't be doing that again anytime soon.

[srobinson]

Are you getting any water in at all? Are you hearing that click at the top of the pull?

[roadman]

I'm getting water in but the steam coming out of the steam arm is anemic and I have to pump the lever up and down like mad to get to get water through the group.

At the top of the pull I'm feeling a click but not hearing it.

Jon

[Kaarina]

Hi,
I asked Pavoni directly and they said the big bubbles mean the machine should be readjusted by the service center, as this indicates a problem with the pressure switch.
Kaarina

[srobinson]

So if you lift the lever with no coffee in the filter..water will come rushing out? Just trying to cross out all the dumb mistakes I have done putting these back together.

[HB]

I'm getting water in but the steam coming out of the steam arm is anemic and I have to pump the lever up and down like mad to get to get water through the group.

At the top of the pull I'm feeling a click but not hearing it.

Jon

Steve is busy with his Olympia rebuild this evening, but mentioned that it's possible the lever is upside down. Look closely at the picture below that I borrowed from another thread (Pavoni in background):



See how the pivot hole is off center? Did you install it with the same orientation?

[roadman]

Well, live and learn. Yes the arm was upside down. Now the water gushes without pumping. Thanks for the help on that one.

Still not enough pressure coming out of the steam arm, but I'm hoping new seals will correct that problem. Am I on the right track or could it be some other problem?

Jon

[roadman]

Well, looks like the seals are not the problem at this point.

Since the machine was de-scaled the pressure relief valve has been acting strangely. It has been making funny noises as it warms up before it starts to whistle. It's letting off steam way too early.

No water goes through the puck until the very end of the stoke. It's not dependant on the grind either.

Is it possible that the spring in the pressure relief valve is messed up? It looks like replacing the spring is a simple repair - any caveats before I go in?

Jon

[HB]

Is it possible that the spring in the pressure relief valve is messed up? It looks like replacing the spring is a simple repair - any caveats before I go in?

Although I don't own a La Pavoni, curiosity led me to search for a little background information (*). I found a hobbyist site on maintaining and repairing them; the advice on troubleshooting steam leaks looks promising in that it covers repairing the pressure relief valve in detail.

(*) Steve promises to loan me his so I can educate myself properly.

[cannonfodder]

I would put money on the pressure relief spring in the cap. It should be quite stiff if you push on it with an ink pen.

[roadman]

Looks like the spring is indeed the problem. It's pretty flaccid. Just ordered a couple from the east coast as I was unable to find one in stock here in California. Hopefully it will arrive before it's time for me to hit the road again next week. Otherwise this will have to wait until I return home in December.

Thanks to everyone for the help and support.
Jon

[roadman]

Quick update: the spring arrived just after I left, so the repair will have to wait until December.

In the meantime here in Bern I've repaired my friends' Europiccola by doing a simple seal replacement. Since their leaky machine was brought back from the dead without having to bring it to the shop for expensive repairs they now think I have magical powers - a sort of an appliance healer. I tried to tell them it was just stuff I picked up on the net but they're having none of it. Wonder if their delusional state was brought on by a sudden massive infusion of caffeine into their nervous systems, having been without for so long.

Jon

[Madroaster]

Quick update: the spring arrived just after I left, so the repair will have to wait until December.

In the meantime here in Bern I've repaired my friends' Europiccola by doing a simple seal replacement. Since their leaky machine was brought back from the dead without having to bring it to the shop for expensive repairs they now think I have magical powers - a sort of an appliance healer. I tried to tell them it was just stuff I picked up on the net but they're having none of it. Wonder if their delusional state was brought on by a sudden massive infusion of caffeine into their nervous systems, having been without for so long.

Hi Roadman,

I'm the guy with the nasty bubbly shots you referred to over on CG. It's been a long time since I've seen them, and looking at the thread again, man...those are gross. Anyway, I just wanted to let you know what happened in my case. The problem went away. I paid very close attention to grind, used fresher beans (started roasting), and, well, the problem went away. Maybe I just got better with the machine...they are tricky at first.

Cheers,
--Derek

[bsafnuk]

Has anyone come up with the cause of these bubbles? I am getting the exact same problem with my Pavoni. Somehow the group is not expelling all the air at the top of the stroke - I know this because the lever is quite soft for the first part of the pull.

Anyways, I am baffled as to what is going on - I have brand new seals on the piston, the handle is installed right side up. The bubbles appear regardless of freshness of roast (both with coffee roasted 2 days ago and with Illy preground coffee). The only variable I haven't ruled out is replacing the gasket where the piston shaft leaves the group. However, I cannot envision how a problem with this gasket would lead to air in the cylinder. There are no obvious signs of problems here (no water leaking out the top, etc.)

Anyways, if someone has some suggestions, I would be very grateful.

-Brad