Hello all,
Just recently I acquired a 2007 Rancilio Classe 6 Leva single group machine from craigslist. The guy said it was used very very lightly at a small bakery but then closed (Machine still looks new), so he just wanted to get rid of it, and at a very reasonable price I might add . This is the first lever machine I have ever used, so please bear with me through this post. Once I got it home I plumbed it in, filled the boiler (it has a sight glass so I could easily tell it was full), then let the machine heat up for 30 minutes. I then tried to make an espresso (Mazzer Super Jolly w/ new burrs) and the lever only wanted to push out tons of steam and very little water ( around .25oz). To do this I prepared the same I normally do with my Rancilio S27 pump machine. I put the portafilter in the machine, held the lever down to pre-saturate and could visibly see the ring around the bottom of the portafilter with water coming through, released the lever and it immediately returned to the upright position giving no resistance and only producing approximately 1/8oz espresso. I then put in a blind basket to see if it would choke the machine and keep the handle in place at a lower position, without success. The handle went back up with no resistance and produced a lot of steam as the result.

From this point I turned off the machine, waited for it to cool, then tore down the machine and did a full descale of the boiler and connecting pipes to the group. Thinking it might have been bad group head seals because it wouldn't create any pressure, so I purchased a new group head seal from EP along with the two seals that go inside of the lever mechanism to pull up water. The descale showed there to be very little scale in the machine or pipes, showing its little use. I then put it back together and tried again to choke the machine with a blind filter (no luck). Once again it would not create any pressure and the handle would go back into its upwards position. As a side note, I also pulled the handle down and left it down to see how the water would pour out if just left open. It produced a LOT of steam and some water, then slowly progressed to only steam. The boiler water level at this point was still high, It just stopped producing water at the head.

I thought maybe there was a leak in the HX style portion of the boiler, but with its little use and that it looks to be in such great shape I am now stuck trying to figure out what it might be. Anyone have any ideas?

(like the problem here Rancilio Classe 6 LEVA Single Group is now mine! but there wasn't a solution listed)

Yes that's correct. I shouldn't have used the term hx as its a thermo-siphon machine. The two tubes inside of the boiler is what I was referring to in the post above. I did replace the gaskets so that shouldn't be the problem, and the water was filled to a high level in the boiler. I'll try raising the water probe to a higher point and see if it will increase the water in the larger tube inside the boiler. I wouldn't think the level it's currently at wouldn't be high enough either. I'll post pictures and hopefully a video of the problem as soon as I get home.

Does it stream water like it would out of the hot water tap?

I wouldn't mess with the water level sensor till you have check out the more obvious. Like the piston seals.

I have a classe 7 leva which is the same machine:) If you need any tips or tricks just send me a pm.

Unfortunately it doesn't run water out of the group like the hot water tap. It actually steams A LOT and only dribbles out water. I actually already replaced the piston seals and the group head gasket. I will pm you though.

It's not so hot that it's flash boiling, is it?

The boiler gauge doesn't work on it coincidentally, but I tried lowering the pressurestat by quite a few turns thinking it might be the issue with no luck. I can also lower it more tonight and look for any visible changes in the water out of the group head with the lever down.

I've used a Classe 9 before, not that's it's worth much for this machine.. but I've never seen a Rancilio flash boil for more than 1 second. How is steam? That would be one way to tell how high the pressure is.. it should be forceful.. but not so forceful that it's super loud.. if it sounds like steam gushing from the boiler.. it's too high.

Fixing the boiler gauge will go a long way and you will need it anyhow. My only other thought is that there is a spring check valve in the group.

Start with fixing the gauge and I would order up more seals since they will need to be replaced annually. Include the shower screen in your order as it can be damaged easily when removed and they are ~$10.

Videos will help.

If it's not a blockage, then the only other time I've seen something similar is when I've used a machine with a broken or improperly set pstat. In this case, the boiler didn't reach a high enough temperature to bring water through the group. Bringing down the lever will give some hisses, spits and steam, but no gushing of water. You can also do this by trying to pull a shot too early as it's heating. I'm assuming that your machine has a false pressure valve?

-phillip