Did the L1 (2012-2016) ever ship with high performance seals? Stuck thermosyphon

Jack Blackmore

Does anyone know when the Londiniums started shipping with the new high performance seals? Unless I flush between shots the lever's not grabbing until very late / high angle and I'm getting a low shot volume, also if I don't flush after the last shot I'm almost guaranteed a stuck thermosyphon.

I think air's getting into the thermosyphon between shots as there's an audible 'pfft' when I flush, also if I forgo the flush when I pull the lever down slowly the water gargles into the brew chamber as opposed to almost no noise if I've flushed before hand. Could it be anything apart from the seals? I bought my machine December 2016 so it's fairly new.

As a side note, I found this cross section of a lever group on HB, is this a fair reflection of how the seals are working with the thermosyphon?



Cheers!

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Matthew Hoffman

I put the high performance seals on my L1 (pre-2017) a few months ago. If I combine them with adequate pre-infusion, I regularly get a 45º lever catch. However, as with the original seals, I do have to flush after each shot in order to avoid thermosyphon stall. As it seems a good idea to do a cleaning flush after each shot, anyway, this doesn't bother me.
Matt

Reiss Gunson

hi jack

thanks for posting. your machine is under warranty so its a non issue - i will get a set of HP piston seals & group seal out to you; if you can drop me an email with the address you want me to send it to

i would of course be most interested if you can tell me what seals were fitted to your piston when you pull the group top - it most definitely should have the high performance seals on it

the high performance seals look like this (the hub is taller by approx 1mm - cf the original seals which are the same height at the hub)

Attached files

Jack Blackmore

Thank you Reiss, i'm happy to pull the group tonight and take some pictures of the seals before you send replacements out if that helps?

Reiss Gunson

either way they're stuffed so I've got to send you replacements regardless

i would be surprised if you have the HP seals in your machine, but we're about to find out

reiss.

Jack Blackmore

Just replaced the seal and it definitely looks like they were the high performance ones. When I took the piston out there were faint marks from the top two seals and the very top one only just cleared the inlet hole. Sorry I didn't take any photos.

Also it looks like there may be water getting above the top seal as the piston was dirty but I could be wrong, does this look as expected? I've never had water come out the drill hole at the back so not sure if this is the case

Just fired it all back up and although it's working great with perfect grab position im still getting the little airlock although I'll test properly tomorrow.

Reiss Gunson

hi jack

its a pity you didn't take any photos, but anyway

if water was getting above the top seal it would be pouring out the drain hole in the back of the forging - that is exactly what it was put there for - and the spring would be going rusty too

i can't readily tell from the above image but the top two seals (those above and below the white ptfe insulating ring) need to be 'open' side of the V seal toward the ptfe ring - these two seals stop the water heading up or down when the machine is at idle

the bottom seal does more work, taking the load each time the lever is released from the locked down position, stopping water heading past the seal as the piston travels in a downwards direction. the open side of this seal needs to be downwards, i.e. the side facing the portafilter

i dont understand the 'airlock' comment. if a tiny little flush (30mL is enough) is performed after each shot on the L1(2012-2016) the thermosiphon will not vapour lock.

Jack Blackmore

This all makes sense, I'll keep doing the very short flush between shots and I'll recheck the metal above the top deal in 6 months or so. I cleaned it all back so should be easy to check, only thing I can think is if it's anything it was a few drops getting above the seal and sitting there.

I'll report back when I know more