La Marzocco Linea Mini - No flow from group

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Beezer

#1: Post by Beezer »

I have an older Linea Mini from 2015. It's plumbed in and connected to a water softener and filter from Chris' Coffee. I've never descaled it, but it was recently in for service at a professional shop, Great Infusions in Santa Cruz, and it's been working well since then. They replaced the group head heating elements and supposedly checked the machine over to make sure everything was working well.

Yesterday I pulled shots and steamed milk in the morning with no problems. However, when I tried to pull a shot yesterday afternoon, no water came out of the group. I can hear the pump running, but no water comes out at all. The hot water and steam are fine, but nothing from the group. I tried removing the screen and running the pump, but nothing. No water comes out when I backflush either. I checked the brew group but didn't see anything obviously wrong.

I'm thinking there's a clog somewhere in the water line to the group. Maybe the gicleur. Anyone have any suggestions? Thanks for your help.

Eli
Lock and load!

limonengelb

#2: Post by limonengelb »

I would also vote for the gicleur. Clive has a good video on pulling it out. My flow rate was about half as expected before I pulled it to clean it. Had some black residue in it. used a sewing needle to ream the hole out.

User avatar
Jake_G
Team HB

#3: Post by Jake_G »

Could also be a faulty coil on the 3-way brew valve.

You can check to see if the solenoid is cycling when you move the brew paddle by listening closely with the top cover off. Careful poking around there with the power on. As LM likes to run constant hot wires to the coils and switch the neutral lead, so things like feeling with your fingers or using a mechanic's stethoscope, while useful, must be done with caution.

Cheers!

- Jake
LMWDP #704

Beezer (original poster)

#4: Post by Beezer (original poster) »

Well, I took apart the group solenoid and soaked the gicleur and three-way valve in vinegar, then poked a thin needle into the gicleur to clear any scale. I didn't see any obvious obstructions in the valve or gicleur when they were out. I reassembled, and at first the water flowed normally through the group. However, after a while it stopped flowing again.

I then ordered up a new gicleur (0.8 mm version) and installed that. I also opened up the brew boiler, siphoned out the water inside, and tried to clean it out with a paper towel to remove any loose scale or debris. It looked pretty clean in there. Again, everything seemed to work fine after reassembly, but stopped working after I pulled one shot.

Now I'm just frustrated. It seems like there's some scale or crud that's loose somewhere in the system, and it sometimes settles down and opens up the water flow, then it gets stirred up and blocks the flow again. But where is it, and how do I remove it? I'm thinking about removing some of the copper water lines that feed into the group and soaking them in descaler.

This is really annoying. If I have to, I'll take the machine in for service, but the nearest company that works on La Marzocco machines is in Santa Cruz, which is a three-hour drive one way from Fresno where I'm located. I just had the machine serviced in December to fix the brew boiler heating elements, and it's irritating to have to waste almost two full days to take it back for another service so soon. So that's my last resort.

Thanks for any suggestions.

Eli
Lock and load!

limonengelb

#5: Post by limonengelb »

So when you move the paddle and get no water flow, you still hear the solenoid click and the pump runs? If you shut off the machine and allow it to fully cool, then warm it back up, does it run a shot again? This guy talks about the controller board going bad overtime due to heat and/or power issues and leading to intermittent problems, one of which being delayed or no shot when attempted. If you really aren't seeing debris or excessive scale, then maybe the issue is electronic