peacecup wrote:I wonder if I could bolt a Cremina group on the PV boiler?
PC

I said 27mm. Mismeasured. Sorry about that. Not enough coffee. The bolts are 30mm on center apart.
Timo

moved

moved

Mine had the lead still intact around the element. Some type of sacrificial anode was my guess, though lead seemed an unusual choice. I removed them.

The piston seal is only an o-ring on la peppina, so I'd suggest McMaster Carr (http://www.mcmaster.com). If you can remove yours and measure it, you should be able to find a suitable replacement in McMaster.

I can't recall how I removed the piston spring assy in mine. I didn't get hurt, but that was mostly luck. I reassembled in a different order. Don't remember how I did that either.

There is a clamping bolt on the back and a set screw on the front. Both of which lock the cylinder into the base assembly. If you leave the piston attached to crank at the end of the lever, the spring will remain constrained, and there *should* be no surprises.

The spring on La Peppina is quite hefty. I think I have some pics of it on some earlier postings in this forum.

Re-assembly is possible by hand (without a large compression tool), but it's not much fun, and an assistant to tighten the setscrew or clamp would be helpful.

And the obligatory warning:
**Be careful when disassembling! The spring is large and strong and it is possible to let it release its energy suddenly. That can be harmful**


Hope that helps.

ciao

lino

Thanks, Lino, for the helpful information. I do indeed recall your picture of the Peppina's hefty spring set beside the Elektra's, iirc. I am proceeding with caution, and that I've never done anything like this before makes me all the more cautious.

I have studied the exploded parts view to which Dr Jim directed me, and it looks to my unpracticed eye as though there's nothing holding the heating assembly chassis to the base but the set screw in front, perhaps some friction against the o-ring on the piston, and, if I understand the function of the clamping bolt at the top rear of the base (#1172 in the schematic), the squeezing effect upon the base cylinder when that bolt is tightened ... though the base cylinder does not appear to expand visibly when the clamping bolt is removed.

With the spring still attached to the crank at the bottom of the lever, I removed the small set screw from the front of the base and removed the clamping bolt from the top rear of the base cylinder. With the lever depressed fully, the heating assembly chassis rotates freely in either direction (after application of some edible mineral oil around the chassis's cylinder where it enters the base) but the chassis does not appear to screw out of the base cylinder and it refuses to be pulled up and out. I'm not sure what to do at this point. I was hoping to expose the top of the piston without having to remove the spring completely, though perhaps that's not possible?

Is the clamshell on the back of the base cylinder meant to be pried apart slightly?
Regards
Timo

Back view of Peppina base with front set screw and rear clamping bolt removed and heating assembly chassis rotated:


View of Peppina base with heating assembly chassis rotated (the lever allowed to rise after the rotation):

That should be all it takes...

Should being the key word here...


Try this.

Cycle the lever up and down a bit while lifting and turning the group assy. That might help it work its way out. Piston friction may be stopping you now and by moving the lever, you might be able to get the spring to (safely) help.
I did have to pry the clamp open a little to get things going.

There are no threads between the group and the base, just a smooth bore, so pulling with a back and forth twist is generally the best way to remove.

ciao

lino

lino wrote:I did have to pry the clamp open a little to get things going.

There are no threads between the group and the base, just a smooth bore, so pulling with a back and forth twist is generally the best way to remove.

Yes, prying the clamp open by tapping a little stubby screwdriver into the slot did the trick. The chassis then twisted right out as you described.

The piston has a little oval hole (marked with a dotted arrow) whose shorter diameter is ~3mm, and the piston cylinder behind the group has a similar hole (marked with a solid arrow) directly behind the group, about 1mm or so down from the "ceiling" as it were.

The screw (part #1154) holding the rubber washer (part #1130) is frozen. I'd be grateful for suggestions on how to loosen it. I will try tapping on the screwdriver with a hammer and maybe the vibrations will loosen it.

I haven't quite understood how these two holes work in concert. When the piston retreats, water in the boiling pot flows by gravity down through the hole behind the group, filling the chamber. But when the piston is forced up again by the spring, compressing the water in the chamber, why wouldn't the water just shoot back up through the same hole back into the pot? How is the water forced out through the group and not back up into the boiling pot?

timo888 wrote:While I am on the hunt for piston seals, and some tiny circlip pliers, let's have a look at the heating element:

image: http://www.aimsdata.com/tim/espresso/peppinaheatingelement.JPG

Tim,
Think of a 2 cycle engine!!! The circles around the center bolt show n in your photo, are in the ceiling of the piston cylinder. They ( under the flexible washer) are the actual intake ports to fill the cylinder. When the handle is drawn down- the flex of this washer allows water to be sucked in. When the handle is released, the flexible washer is pushed against the intake ports and finds the only way out is through the exit port( the one you mistook for the intake port. It then is expelled through the group head.
You did ask about how to remove the screw . First is the rubber washer in good shape? I would be cautious of using anything other than mineral oil to act as penetrating fluid so as not to contaminate a flavor enhancing component that you may or may not be able to find a replacement for.

What he said...

Additionally, you may note that the outlet from the cylinder has a one way valve (out only) as well. The little rubber disk in the center of the group. I guess so that mid-stroke re-pumps are certain to take fresh water instead of the stuff over the coffee bed.

Also the washer and stuck bolt that allow water in from the tank should probably be left alone. There's nothing behind it besides a few holes, and that poor piece of rubber is getting old and tired.

The little hole in the piston is to allow water to continue to flow into the group even when the piston is above the port to the group. (don't think 2-stroke on that one... )

ciao

lino

mogogear wrote:The circles around the center bolt shown in your photo ... are the actual intake ports to fill the cylinder. When the handle is drawn down- the flex of this washer allows water to be sucked in. When the handle is released, the flexible washer is pushed against the intake ports and finds the only way out is through the exit port (the one you mistook for the intake port. It then is expelled through the group head.

Ah, I see. I poured some water into the 8 holes of the base and held it up and peered up into it, and thought the water seemed to be coming in through the oval shaped hole. Now that the thing has dried off, I've tried it again, tilting the side opposite the hole down. I see that the water entered from behind the flexible washer, and the area near the hole remained dry.

Is the flexible washer in good condition? I frankly won't have a baseline to compare it to (when I manage to unfreeze the screw) as this is the first espresso machine I've ever taken apart and my first encounter with flexible washers. I can say that the washer is intact with a clean edge, not crumbly. But I wouldn't know from sight or feel if it were too flexible or not flexible enough. When I swipe it with the tip of my finger, the tip of my finger gets stained black, if that's any indication of whether it needs to be replaced.

Regards
Timo