timo888 wrote:Is there preload on the spring beneath the plate?
Que?
I am not sure what you mean? The lever spring? If you mean by preload is the spring held under pressure- yes...
When I originally tested the machine- the group leaked. There is an airhole on the top back of the group to allow the air in the top part of the piston to escape when the lever is released. Water starting bubbling out there. so I took the group apart- At first I undid the two hex screws and nothing happened- I pulled on the lever but no movement- so then I undid the lever and released the spring ejecting the filter plate in the process. The piston has two seals on it- one is a V section (bottom) and one a double V (top-V on both sides). The seals were quite good- so I cleaned them- lubricated heavily with Dow 111 and reassembled. I had a lot of trouble getting the spring pushed in to re-attach the lever- Until I used a clamp to slowly wind the spring in- so easy. Then I tested again and there were no visible leaks. But I am not sure if the first V seal fails then maybe coffee/water could escape from the piston into the boiler.
Thinking about it now- I think I will take the spring out again and post pictures of the seals to see if they are still available...
one hour later:
Not so easy... I undid the hex screws- and nothing- cannot put the lever and spring out- they won't budge at all- looks like the seals are pretty tight. There is nothing stopping the entire assembly pulling out- except the seals against the piston wall.
I could clamp it and release the lever again... but maybe I should just leave it as is? In my last tests there were no leaks...
Doug- do you have a spare boiler cap?
And with the water inlet- I would have to use the filler hole at the top right? If I ran an elbow and some pipe down the rear of the frame and had a valve with a tap mounted on the side- do I need some kind of valve to let the air escape as water goes in? Forgive my ignorance here- this is the first machine like this I have worked on.
I was thinking perhaps I could put a Tee on the boiler filler hole- and have one pipe either rising up through the stainless cup tray (via a hole I will reluctantly cut)- or out the rear of the shell- for manual filling, and running the other one down to the base for a plumbed line. If I had a tap on the plumbed line at the T- then it could all sit there waiting for a time when it can be plumbed in.
but then there is part of me that just wants to put it back together as is- get a small funnel-plug the boiler with something and go for it.
The thermostat worked fine when I tested keeping the machine at 1 Bar steady (if the gauge was still accurate). Should I consider replacing it? Or just change the seal and put is back?
Reading on OE about the Ponte Vecchio- I see it has some kind of high temp safety switch- is there something I should fit to this machine to protect it against a dry boiler meltdown?
and then I was wondering about fitting a different steam arm assembly. Some Retro one like on the Ismomac Alba:

The steam arms that that are fitted are a bit of a joke to look at- no nozzle- just one big hole- no movement- impossible to get a large jug underneath the steamer... I really like the toggle/screw valves they have bu that's about it...