Gatewood wrote:Man, those look rough! Mine are straight, and shiny. Yours look rusted. Not sure how that is possible.

The 'slider' also looked like that!

Gatewood wrote:Anders, I don't understand. You say the piston only travels a few millimeters before it blocks the hole. Mine has the hole blocked when it's up all the way (although the grey stuff might be responsible) although I can blow a little air through. It's when it's on the way down that the hole is blocked so that I can't blow air through. Is this correct? Do you ever actually see the intake hole when the piston is all the way up?

Hi Gatewood, visually the intake hole is always blocked. It can't be seen because the lower part of the piston covers it, but water and air can get past. If you blow through the tube, with the piston all the way up, the air will escape through the intake hole. This is what happens when you raise the lever during normal operation.

When you lower the piston, the gasket on the piston will block the intake hole. Not just visually, but also physically, and the flow of water or air stops. This situation continues during the complete movement of the piston, which corresponds to the actually pulling of an espresso.

So you should only be able to blow through the intake hole, with the piston at the top. On my machine the flow of air is very free, sort of like blowing through a straw (McDonalds-type, not the thin ones ) Because of the design, the only way this can be tested is to be sure the piston is at the top, and then blowing. You can can find som other way to make an airtight seal around the top of the group head, this could also be a possibility.

Smile

/Anders

More experimenting will have to be done when my replacement parts arrive. They are supposed to get here on the 29th. At this point, I can't do anything, as the gaskets are off the piston, the piston is out of the group head, and the piston shaft is unscrewed from the rest of the piston. Pieces of brass and Pavoni innards in a pitiful little pile in the kitchen. So, for now, I try not to even look at it.

I have my fingers crossed. My parts came today for the Pavoni, I changed both piston gaskets and the o-ring, cleaned out the innards of the group with Joe Glo to get the grey junk out, and reassembled the whole thing. I heated it up and lifted the lever, and got water! Yaaay! Too late to try to pull a shot, as I have an early day tomorrow, but I'll try it out tomorrow and hope it is back in business.

Thanks to all you guys for your good advice and tips on doing this. Next time should be a piece of cake. Putting it back together really went rather smoothly, except for some jiggling to get the gaskets to go back.

Gatewood wrote:I heated it up and lifted the lever, and got water! Yaaay! Too late to try to pull a shot, as I have an early day tomorrow, but I'll try it out tomorrow and hope it is back in business.

Good Morning!

Are you back to the world of espresso ?

Henry

Welcome back Gatewood. Can't wait to hear how your pulls are now. It really IS pretty simple, isn't it?? (once you've done it, of course.... until then, there's that great unknown)

Ken

Just back from a busy day. Yep, I'm delighted to say, all seems to be well. I got plenty of water to pull the shot with, although the shot was anything but great. It was drinkable, at least. So, now, on to Super Jolly, to get used to it so that I can get a decent grind. I tried the first shot on the KitchenAid, since I'm so familiar with it. One thing which surprised me, and saddened me a little. I'm nowhere with this machine, now. The Gaggia Classic I bought for the studio is so forgiving (even with the KitchenAid grinder) and the shots on it are so easy, so full of crema, and so tasty, that my learning curve on the Pavoni just jumped up a major notch. I was 'way better on the Pavoni before it started having trouble. Maybe the constriction from the water helped me out a bit. We'll see. Onward....

(well, at least, I can steam heaps better on the Brass Beauty than I can on the other machine... Too bad I prefer straight shots.)

kbuzbee wrote:Walter, that is so weird that worked for you. Flipping the handle upside down you effectively reduced how high the piston can be raised. If anything, I would expect that to limit the water intake more. Glad it worked for you though. Just another quirk of the Pavoni I guess. Seems no matter what the issue is, there is someone who has managed to find a way (usually through trial and error) to solve it. I often raise an eyebrow at some of these solutions (and fully expect there are those out there who view my journey with a "What are you thinking?" look on their face) Oh well, if it works for you.....

Ken

It seems that is not true for my machine. I recently marked the uppermost position, then turned the handle once again and checked. The piston-rod did not come out any farther, than it did with the handle upside down.

----

Some more news:

When I disassembled my Pavoni once again I was able to trace the source of my problem: When I was buying me a brass piston, the service-technician of the dealer mentioned I should use a drop of Loctite to prevent unscrewing of the piston rod with time and that suddenly sparked the idea where my problem might stem from. And indeed, the thread of the piston-rod was glued in place, but it was not screwed in all the way. Hence it appears that even in the uppermost position the water inlet was partially blocked by the piston. Now that I've screwed in the piston-rod all the way there is ample water splashing out of the grouphead in the uppermost position, actually more water than I was wishing for.

Also, yesterday I have eventually replaced my plastic piston with the brass one, but so far I haven't noticed any significant changes, the piston seems to move a little easier (it appears the brass piston is a little smaller than its plastic brother) and I can now empty the boiler in almost no time through the grouphead.

Especially the syrupy ristretti I love so much are now harder to produce, it was easier when a little less water was entering the grouphead...

Walter wrote:Especially the syrupy ristretti I love so much are now harder to produce, it was easier when a little less water was entering the grouphead...

You can imitate the previous situation by not lifting the lever all the way up.

Interesting that it should make so much difference! Can you describe how the ristretti are different?

Henry

Walter wrote:......

Especially the syrupy ristretti I love so much are now harder to produce, it was easier when a little less water was entering the grouphead...

Time to grind finer my friend, get a little closer to choke-mode. Make that water have to work and spend a liitle more time with your coffee grind..