La Marzocco Linea Mini User Experience - Page 194

Need help with equipment usage or want to share your latest discovery?
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#1931: Post by OK31 »

Don't have the mod so not the best person. Fresh beans less than a week out may very well contribute. Have you tried back to back shots?

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#1932: Post by limonengelb »

I've noticed if the machine sits awhile, like overnight, pulling the paddle does not result in water flow until the pump triggers. If i reset the paddle and try again, I get some low pressure water flow. This might be throwing your timing as well. I have started doing a quick flush each time I pull a shot to eliminate the variability in low pressure water flow. I am running off the reservoir and not direct plumbed to a pressurized water source.

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#1933: Post by Nyles855 »

Did some more testing today. Didn't change the grind setting, but pre-flushed the group head right before pulling a shot and didn't pre-flush before pulling a shot.

When pre-flushing, even if I waited 10 seconds for the shower screen to have no residual water, my shot time was much faster, around 28 seconds.

When not pre-flushing (last time I pulled water in the group head probably would be a few minutes), my shot time was around 40 seconds.

That being said, the output taste was nearly identical, no noticeable differences, but I suppose it's interesting. I do wonder if it's linked to the grafikus mod and there being more water debt due to an increased distance from the boiler to the group. Curious if anyone could test it on a non-modded LM.

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#1934: Post by Chrispy513 »

I'm happy to give this a try on my stock LMLM this afternoon. I've always made it a habit to do a short flush before locking in the portafilter since I got the machine.

How are you liking the Grafikus mod so far? I've been toying with the idea of picking it up as I've had my machine for almost a year and am looking for something else to tinker with.

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#1935: Post by Nyles855 »

It's a good question. Honestly, I got my machine used and didn't use the machine much before installing the mod, so it's hard to compare a before/after. I came from a lever machine, and I found myself missing the "softness" I associated with the gentle PI I got from the lever.

The mod does achieve that, and, overall, I love the machine, and the flexibility the mod provides. I don't think it's that big of a game changer, especially since with the connected kit and having the unit plumbed in you can do some very similar PI tweaking. Plus, you're probably not going to tweak the needle valve setting very much because it's quite sensitive and you have to take off the lid of the unit to access it.

That's not to mention how much of a pain in the ass it was to install. I consider myself very handy and it took me the better part of day to get it done. Even then, I recently discovered a small leak that I had to go back in and fix.

So overall, maybe worth it depending on your skill level and desire to do it. To my knowledge, there's no cheaper way to get a PI capable machine, but you don't have the flexibility that you do with something like a lever or the full ECM mod for the LM.

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#1936: Post by brshap »

I'd have to check the manual again to confirm but, if memory serves, LM recommends a quick flush before pulling a shot.

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#1937: Post by Nyles855 »

Checked the manual and it basically just says do whatever you want haha. It does recommending at least pre-flushing prior to the first brew (before you even prep a puck).

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#1938: Post by Chrispy513 »

Following up on this. Not super definitive, but yesterday afternoon I let the machine come up to temp (~15 min) and then pulled a shot with no flush prior.

Then this morning, I followed my usual routine. Machine had been on for ~30 min, I used same dose and grind, flushed prior to shot like I normally do.

Both shots were within 1 second and 1 gram of each other, so I saw no difference between flush and no flush.

I suspect the biggest difference would be if the machine had been on at temp for a long time with no flush, as that's when I notice some sputtering from the group head during the flush.

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#1939: Post by ntsimmonds »

Nyles - I'm curious if you could run your machine, at full pump pressure, after it's been sitting for some time (30m up to an hour or two), and then run the group at full pressure to see if there is any flow at all

I recently had a problem with my 2016 LM (made a thread for it La Marzocco Linea Mini - Brew gauge at 0 bar, flow delays at group) where the underlying issue was actually 3 failed check valves between the pump and group head. Essentially, since the checks couldn't resist the backpressure, water would flow all the way back through the pump from the group head. So the group head would still heat up, start evaporating the water in there, and since it couldn't move forwards through the group, it pushed everything back through the plumbing to the pump/tank. The apparent symptom being that if the machine sat for a while (I am an always-on guy), and I activated the group, it could be 10-15 seconds of nothing but air flowing through the group.

Like you reported, this didn't actually affect shot quality, but it did take a lot of forum searching, video-watching, etc. to actually come to this conclusion. Since you got your machine used (how old is it?), I'm wondering if it could be suffering from the same issue.

If you do end up replacing the check valves, someone posted a link in that thread I mentioned to a UK company that sells them for around 23 GBP, and the cheapest US retailer I could find has them at ~$55 USD, so almost double

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#1940: Post by Nyles855 »

Thanks Chrispy for trying it out.

And yeah I'll try it out. Usually, when I first use my machine in the morning it's been on for 30-45 minutes and when I first flush it tends to steam a little bit, but it's steam/water. I linked that issue to boiler temperature, though I've always kept it around 208 and it did seem to decrease when I replaced my group thermofuse. I'm not an always on person, and it's both water and air flowing through the group when that did occur.

I'd have to check what year my machine is, but 2016 sounds right. How else did you diagnose the issue?

Edit: Checked it out today, don't think that's my issue. First pull after the machine was on for ~1 hour and there was no steam/air.