Hi-

First post here, thanks for the great forum. I tried to do due diligence with a forum search and didn't see anything. If this has been covered in another thread, I apologize.

I have a La Pavoni Millenium that I bought used off eBay. Been making coffee everyday for six months or so, and while I'm no pro (and while the machine has all it's befuddlements), I'm a happy camper.

Recently, though, less and less hot water / steam began coming through the group head valve. Not the steam wand valve, but the valve between the boiler and the group head. Now, when I raise the lever all the way (even with the portafilter off), sometimes *no* hot water comes through, and sometimes some trickles through, and sometimes about half what used to normally comes through. I have to really crank the lever all the way up in an almost hard, jerky motion to get the water to come through, but again, it's random - sometimes it trickles, sometimes it flows, but not at regular volume. The machine is definitely hot and up to temperature.

I have tried cleaning (several times) with a light vinegar solution and letting it run through the valve and out the group head. There doesn't seem to be any scaling in the tank. Machine seems otherwise in good order, barring some seals that are soon going to need replacing.

Any hints?

Is this something anyone has experienced?

I'm wondering if I somehow pulled some espresso grounds back through the valve when double pulling a shot. I don't know. Thus asking you all.

THANKS for any input,

-Alex

You might first take a peak in the boiler with a flash light or a camera phone to see if the group feeding tube is still in place. I think there was a run of millenium machines with a bad plastic connector between the tube and the group (pre-milleniums thread the tube directly into the group). See if the tube is loose in the boiler. I've repaired one such machine myself and have seen others on the coffee forums with a similar problem. I think a replacement part is about $10.

There isn't a valve between the group and the boiler in the same way that there is a valve in the steam wand. You may have some buildup in the lower piston seal (coffee, lube, something else...) that's preventing it from letting water through. If you are feeling up to it you should take out the piston, remove the seals, and clean out the channels...you will need some DOW 111 to reapply to the outside of the seals (not in the channel), piston chamber, and rod for reinstallation. If the seals are stiff or hard then now would be a good time to get new ones.

Also check the piston hasn't become un-screwed from the main shaft, as the millenium plastic pistons were prone to doing.The piston ends up lower, and blocks off the group port

Thanks. I'll get on with all of that.

I'm sure there are zillions of resources online and in this forum (and I'll get on searching for them) but if you all have a good guide for taking apart the group to access the piston and seals, I'd appreciate it.

-Alex

kitt wrote:Also check the piston hasn't become un-screwed from the main shaft, as the millenium plastic pistons were prone to doing.The piston ends up lower, and blocks off the group port

+1 on that

Another possibility on the millennium is that you have some lodged-in scale blocking the water path inside the group right where the water channel enters the plastic sleeve. (a Pavoni owner reported this on Coffee Geek a year or so ago - https://www.coffeegeek.com/forums/espre ... sso/562639 ) In that case the owner had to remove the plastic cylinder from the group to find the scale and clean it manually.

kitt wrote:Also check the piston hasn't become un-screwed from the main shaft, as the millenium plastic pistons were prone to doing.The piston ends up lower, and blocks off the group port

I think this was it! I just took apart the group head (not so hard with two glasses of wine in place of instructions) and the piston was a bit unscrewed. Which makes sense for why it was then a bit lower and not letting (enough) water through.

I'll also check for scaling and for lubrication as others have commented.

You all are FANTASTIC.

Thanks,

-Alex

LaPavoniHome wrote:I'm sure there are zillions of resources online and in this forum (and I'll get on searching for them) but if you all have a good guide for taking apart the group to access the piston and seals, I'd appreciate it.

Start here Refeathering the Peacock - Pavoni head gasket replacement

That advice is pre-millennium, so doesn't tell you how to remove the plastic sleeve, but that's easy. The sleeve has two notches, you fit a something into those notches (Stefano's espresso care sells a little metal bar for that) and screw it out CCW.

Two things:

1) My La Pavoni has so much water flowing through it that Niagara may send a copyright infringement claim. It's never been like this before. Nice!

2) I just made two test espressos and they were two of the best I've ever pulled.

Now to figure out how to get to sleep! More wine!

THANKS for the quick help,

-Alex

Good to hear its fixed, but.... if its happened once, it may happen again. The 2 options for a permanent fix are;

1- Replace the plastic piston with a brass piston, they don't seem to have the same habit of un-screwing

2- Secure the plastic piston to the rod with a medium strength food safe thread locker

You're fine to use it for now, but if the flow becomes restricted again, at least you know the possible fixes

I now use thread locker even on brass pistons, they have also unscrewed for me.