I also like my shots to require firm pressure, yet recently I loosened grind one whole notch (on mini) and now it's much more fun to pull. But I use a bit of tamping - puck is some 2 mm below the screen.
Peacecup, I'd think going up with the lever could disturb puck, not going down. You meant the opposite?

Well, it was a very sad day today. I have been having trouble with my portafilter gasket for the last couple of days - just ordered another figuring that would fix the problem, and kept cleaning and reseating it in the meantime. Then, as I pulled a shot today, I blew the whole head! Literally, the head partially separated from the piston body/ portafilter unit. I didn't even know this was a separate piece. And I'm at a complete loss as to how to resecure it. (when i say head by the way, I mean the pat which the basket attaches to).

I hammered it back on and reseated the gasket, ground a bit coarser and tried again. The pull wasn't even that tight, but it blew again.

Anyone have an idea?

Thanks all!
Jon

Holy Mackerel that's a new one! From the looks of it the group bell is spot welded on. I agree....I did not know it could come off! I think you are going to have to have it welded....just a couple of MIG wlds around the sides. Sorry it blew but what a surprise!

Sorry to hear!

I'm surprised as well.

Some quick photos of the Caravel grouphead and piston chamber, cleared with a soft brush:

and a close-up:


Sure it does not look like one part, but I wouold never have thought it'd be possible to tear them apart. And I choked my machine twice recently, mind you, and believe me - I was leaning on the lever with all my body. Will not repeat it though after reading this story

Well, that is the first mechanical failure we've heard of here on the AC thread. I'm sure its fixable, but it will be inconvenient. That said, I haven't used the Caravel for a couple of weeks myself. But I just took it out to look at the group head, and then, well, maybe just one...

I guess this is an argument for not pulling TOO hard, but I guess it must be a pretty rare failure.

Good luck getting it back in action again!

PC

CoffeeOwl wrote:I also like my shots to require firm pressure, yet recently I loosened grind one whole notch (on mini) and now it's much more fun to pull. But I use a bit of tamping - puck is some 2 mm below the screen.
Peacecup, I'd think going up with the lever could disturb puck, not going down. You meant the opposite?

Depends which version of the piston you have. The pistons with the center hole and tiny o-ring shouldn't cause any suction through the puck with going up, as it's designed so the piston drops enough to break the o-ring seal and allow air in from the top of the cylinder, thereby leaving the puck undisturbed. The pistons without the center hold and o-ring could suck air through the puck.

You can see the pictures of piston earlier in this thread - it is one with the hole in its center.
However, as I already explained, there is a difference going up with the lever while the boiler lid is closed vs while the boiler lid is open, and it can also be felt with hand pressed against the bottom of the piston cylinder. When the lid is open, air gets more easily from the top.

p.s.
oh the photos were on page 6 and actualy the piston bottom is not visible on them - I'll post another photo tomorrow.

Quick question - if the kettle is full and I raise the handle all the way, after the gurgling stops, the water continues to fill up in the piston and will eventually start to come out the sides if I don't start pushing down. Is this normal? From the design, it appears that lifting up allows that hole in the bottom of the piston to open (where the little o-ring is), so I don't see how this *isn't* supposed to happen.

Just checking to see if anything is wrong. Thanks!

That was normal for me.