I purchased a Ponte Vecchio Lusso from Vanelis last week as an upgrade to a Gaggia Classic. I read up on this and other forums, and was prepared for some not-100% build quality. But aside from some residue and crud in the boiler, and the pressure gauge being tilted slightly, it looked pretty good. I should point out, also, that Vanelis double boxed it VERY well.

Where I need help is: the lever has started slipping up (jumping from the bottom of the stroke) as though the (brand new) gaskets are failing?

I've made about 20 shots so far and attributed the first couple of "slips" to my grind/dose etc. as I was dialing things in, and the fact that I didn't have a proper tamper for the first few days. I haven't been able to make a great shot yet either. To counter the slipping, in case it was due to too coarse a grind, I went so fine that I was getting oily, over-extracted coffee. And have been moving more and more coarse, but the lever has started slipping every or every other shot. Most shots are vaguely to undrinkably sour. The pressure seems to float around 1.1 - 1.3bar.

My procedure:
Grind 15 grams of coffee (have tried 14-17g); tamp; insert portafilter as normal (have also tried locking it in after pulling the lever down halfway and that has had no discernible effect); gently move the lever the final few degrees so water flows; hold for preinfusion for 4 to 7 seconds, gently release lever. At this point, it will frequently slip back up 10-45 degrees with almost no drag before it seems to catch. Sometimes, after this point, it will operate as normal from here and I can drink the very ristretto shot or take a second pull. Not sure if it's of any consequence, but when it isn't fractured, the top of the puck looks wavy or sort of lumpy when I remove the portafilter.

So my long-winded question is: is there something in my technique that's at fault or have I purchased a lemon?

Thanks for your help!

I should probable add that I do let it come up to temp, bleed off false pressure, then let it warm up for 10-20 more mins before I even touch the lever.

Also, the lever slipped up the third time I ever used the machine. So I don't think it's a question of parts wear.

I don't know of any lever that grabs immediately, and my experience ranges from manual levers like the Caravel and Cremina to commercial spring levers. There's always some air in the group cylinder, and air is compressible, so the lever will move fairly freely until the air is sufficiently compressed to offer full resistance.

There's always a small amount of movement from the bottom of the stroke, but the lever will (about every other pull) pass this point and travel a few more inches (sometimes half of the stroke) upward with no resistance at all. It doesn't seem normal to me.

Not sure if it's relevant, but I just used the hot water tap to warm a cup and the boiler water seems to be filthy and slightly brown with fines in it. I thoroughly rinsed the boiler (4 times) before using the machine and just refilled it with clean, filtered water last night. Is it possible for coffee to make its way back into the boiler?

GVDub wrote:There's always some air in the group cylinder, and air is compressible, so the lever will move fairly freely until the air is sufficiently compressed to offer full resistance.

Well said.

To elaborate a little - When you lower the lever, the piston above the puck rises, and air is sucked through the puck into the space above the puck and below the piston seals. When the lever is near the bottom, that seal passes the inlet hole and water is jetted into that space by the 1 bar of boiler pressure. The first few ml of water may flash boil because it is above the boiling point for water at atmospheric pressure. That steam will displace some of the air - water vapor and air flows freely down through the dry puck. Once the puck saturates with water it is pretty well sealed against vapor passage, and the pressure comes up to ~1 bar and all the water vapor converts back to liquid. But still is a some air in there.

If your group is cold, you might expect less flash boiling, with the result that there would be more air.

You can try a little experiment - before locking in the PF, pull the lever down til you get some water and steam flushing through, then raise it just til it just stops flushing, then lock in the PF and pull the lever back down. You probably will see the lever catch earlier and get more volume in the shot. Some people (mostly with manual, no spring, levers) use a method like this routinely.

[edit additn: I posted this reply before noticing duffybike's post above, and see after a more careful read of the first post that group temp, and cocking before locking in has already been addressed. ]

duffybikes wrote:Is it possible for coffee to make its way back into the boiler?

Is possible because there is no check valve to prevent it, but should not happen in normal use. Hope some of the PV users on this forum can advise about that. I'd recommend removing the shower screen to see of you have a lot of coffee above the screen.

Unless your grind is way too coarse the lever should catch soon after it begins to rise, and rise slowly, controlled by the pressure created by the coffee puck. If the puck is too coarse, not enough pressure = fast rise. It can be fast enough to hurt you.

If your grind is fine enough and the lever is still popping upwards it would indicate a damaged bottom piston seal. This is not entirely impossible even with a reputable dealer like Vanelis. A seal can have dried or been slightly damaged at the factory without anyone noticing. A damaged seal can act "normal" 9 times out of 10, or 5 times out of 10. My Lusso currently has a damaged top seal, and I know I need to replace it, but half the time it acts normal, so I have not been in a rush.

Replacing the seals requires patience and moderate mechanical skills, but it is doable.

PC

Shaun made a series of videos of his PVL two group several years ago. Can't find the thread but the videos are out on YouTube. Might be of some help.

Edit: I think this is the thread. Onemoreshot (Shaun) starts here.

Thanks for all the help and the links. In the first video, the lever seemed to travel a bit before he met resistance, so I thought I'd give it another go: rinsed the boiler twice. Kept the grind the same as it was this morning (the last shot I made did not slip). And pulled a shot. Preinfused for 7 seconds, let go, and the lever rose all the way to the top of its travel without any resistance (I kept my hand on it for safety). I pulled it down again and it worked normally. Shot looked good so I did a 3rd (2nd, really) pull and that looked nice, too. The shot tasted quite good. Still a smidgen sour, but clean with nice, almost guinessy crema.

So, what do you guys think? Is it possible that my grind is totally wonky, which is causing a complete loss of pressure on some first pulls? Or is it more likely the lower seal?

I have previously tried it with the grind very very fine (nearly as fine as Rocky would go) and the shots were undrinkable: overextracted, oily, large bubbles, no crema, and it still slipped a little on some first pulls.

I don't know jack about lever machines, but I know the rocky is a marginal grinder at best. Any chance you can borrow a better grinder to eliminate that variable? Are you using a naked PF?

duffybikes wrote: ... causing a complete loss of pressure on some first pulls? Or is it more likely the lower seal?

I'm a manual lever guy and not a PV owner, but it sure sounds like a piston seal problem. The seals flare to get a good seal, and if they're are hard and inflexible they don't flare, and produce no pressure. - Sort of like a Silca bike pump that's been on the shop shelf a long time.

I wonder if they might get better with some intense use. Perhaps cut a sponge to fit your basket and pump a boiler full or two through the system to see if they loosen up and start working. I think if it were me I'd order some Dow 111 lubricant and new seals, and pull the piston and replace them. Maybe just clean and lubricate the old ones if they look like they're fine. Unfortunately, you'll need to rig some tools in order to pull that piston. Here's one person's method for that: