La Marzocco Linea Mini User Experience - Page 165

Need help with equipment usage or want to share your latest discovery?
MESS

#1641: Post by MESS »

I don't have any solid data, but the Voltage 6 Hole Diffuser Screw definitely reduced channeling for me. Channeling has always been something that I struggled with the LMLM.

Jrodanapolis

#1642: Post by Jrodanapolis »

I agree that the Voltage 6-hole screw seems to help with channeling. I always try to prep the puck the best that I can, but it seems that the 6 holes do help in achieving the most even extraction possible.

I'm having an issue with my mini that I can't seem to figure out - when I get done brewing a shot (or flushing, etc.), the pressure drops to 0 bar. I just swapped the plunger in my 3 way brew solenoid because I read somewhere else on here that that may be causing the issue. I was running through a huge amount of water on the tank (planning to plumb soon but not quite there yet), and am hopeful the new plunger will help with that, but I can't seem to figure out why I'm not getting the ~12 bar pressure when the machine isn't operating.

This is a video from before I changed out the solenoid plunger - if you wait until the very end, after water finally quits dripping from the drain in the back, you'll see a not-insignificant amount of water drip from the group. While the pump is running/brewing a shot, the pressure reads 9 bar, so I'm wondering if my diffuser has gotten just a tiny bit loose or the o-ring that's inside the diffuser has gone bad? Machine is two years old (just out of warranty).

It makes great espresso, but I'd feel a lot better if I knew there were no leaks. I also find that when stopping a shot at 36 grams, I end up with somewhere between 50 and 55 in the cup if I don't remove it from under the grouphead right away. Most pucks are really soupy unless I let them sit for a few minutes.

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Jake_G
Team HB

#1643: Post by Jake_G »

What's it doing after you changed the plunger?
LMWDP #704

Jrodanapolis

#1644: Post by Jrodanapolis replying to Jake_G »

Seems like less water drips from that back drain, but it still drops to zero bar as soon as the pump turns off.

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Jake_G
Team HB

#1645: Post by Jake_G »

There are at least three check valves in between the pump and the brew group that should be keeping the group pressurized, in addition to the solenoid.

Have you bled the group lately? Air in the group can make the pressure drop off after brewing.
LMWDP #704

Jrodanapolis

#1646: Post by Jrodanapolis replying to Jake_G »

Ah, thank you Jake! You always know how to fix my LMLM problems. Could you help me figure out how one would bleed the group? I found a video for the GS3, but don't see a bleed screw on the mini's parts diagram.

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Jaroslav
Supporter ♡

#1647: Post by Jaroslav »

flip wrote:TBH if I'd do a blind test with the old vs new screw I would probably not be able to tell the difference. Plus I don't have a refractometer so I can't measure anything. But I'd expect a tiny improvement in extraction since water flows more evenly, and it's also nice to not have the screw touching the coffee bed so often.
Thank you for letting me know. It's worth mentioning that La Marzocco has also redesigned their screw back in 2019. Based on your video, it seems yours is the pre-redesign type of diffuser screw. I've seen these custom screws with more holes on Etsy, but never actually tried one since I already have the "improved" OEM screw and never noticed issues with water dispersion. I'm also curious whether the amount of holes (4 versus 6) has any influence over extraction.

Here's more on that redesigned diffuser screw in case anyone's interested:

https://www.instagram.com/p/B2O-3WXnz4w

OK31
Supporter ♡

#1648: Post by OK31 »

Silly question but does tightness of screw into the port have any bearing on flow? I know sometimes if not properly screwed in (too loose) water tends to go almost beyond the diffuser screen and I've always erred on the side of under rather than over tight.

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Jake_G
Team HB

#1649: Post by Jake_G »

Jrodanapolis wrote:Ah, thank you Jake! You always know how to fix my LMLM problems. Could you help me figure out how one would bleed the group? I found a video for the GS3, but don't see a bleed screw on the mini's parts diagram.
Sorry for the delay!

There is actually a valve on the left side of the brew group for bleeding! (Or for draining... if it's up high, it is for bleeding, down low for draining.) The brew solenoid is actually mounted quite high in the group, so it may be designed to bleed itself when pulling the first few shots from dry.

That said, I'm curious why your plunger failed. Did you remove the entire solenoid valve? I wonder if you don't have a damaged seat or some grit in the valve body.

Cheers!

- Jake
LMWDP #704

flip

#1650: Post by flip »

Jaroslav wrote:Thank you for letting me know. It's worth mentioning that La Marzocco has also redesigned their screw back in 2019. Based on your video, it seems yours is the pre-redesign type of diffuser screw. I've seen these custom screws with more holes on Etsy, but never actually tried one since I already have the "improved" OEM screw and never noticed issues with water dispersion. I'm also curious whether the amount of holes (4 versus 6) has any influence over extraction.

Here's more on that redesigned diffuser screw in case anyone's interested:

https://www.instagram.com/p/B2O-3WXnz4w

Hmmm, there doesn't seem to be much difference. The custom one has 6 holes instead of 4, has an o-ring and is also flat (which does actually help since it sticks out less).