La Marzocco Linea Micra and plumbing/flow/preinfusion

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

#1: Post by espressoren »

In preparation for receiving my Micra this week I've been reading a lot about water quality, plumbing, etc. I have found a few older discussions around this but thought I'd start a new thread rather than revive a long dead one.

What is everyone's experience around plumb in of these devices and running filters? I know some people have specially curated reservoirs and pumps. I'm looking at plumb in and am a bit surprised by the 8L/ 2.1GPM specified by LM. ... ations.pdf

I sort of wonder if this is just assuming you are using line pressure supply and specifying what is considered "normal". For reference, many bath shower heads are only 1.8GPM, and by law can be no more than 2.5GPM in the US or 8L/M in EU. Interesting that their recommended flow rate is the same as the EU max. Additionally, this recommendation doesn't seem to change whether you have a one group machine or a four group machine. ... ssic-1.pdf

To bring this back to application, I'm looking at a water prep that can provide .75GPM, versus filtering the line and providing full line pressure and flow. I don't want to "starve" the machine if it's going to cause suction on a low flow filter system and break things, but at the same time it just seems like 2.1GPM is excessive for such a small machine. I understand that nobody short of an LM engineer probably has an official answer to this but looking for experiences.

Related to this - the decision here will have a direct impact on preinfusion. If I go with line pressure I'm looking at maybe 4 bar preinfusion. With the lower flow filter system it may be similar but the pressure may build more gently. Any opinions here?


#2: Post by PaulTheRoaster »

I'm using an Everpure Claris filter that flows 0.5 gpm. No issues. TBH I hadn't noticed the flow rate in the LM water spec. Does seem really high. The highest draw by far is going to be the first time the machine is switched on, so you could do that off the reservoir then plumb.

espressoren (original poster)

#3: Post by espressoren (original poster) »

Yeah, I'm probably overthinking it. They are recommendations, not necessarily requirements.

Do you have a drain plumbed? I've read that the Micra tray might not have an outlet for drain. I'm not sure it is worth the effort given that I will probably want to clean/rinse the tray regularly anyway.


#4: Post by PaulTheRoaster »

espressoren wrote:Do you have a drain plumbed? I've read that the Micra tray might not have an outlet for drain. I'm not sure it is worth the effort given that I will probably want to clean/rinse the tray regularly anyway.
There is a threaded plug in the tray that can be removed to attach a drain line. I haven't plumbed the drain - it would be quite a job for me to run a drain line.

espressoren (original poster)

#5: Post by espressoren (original poster) »

I understand there's a threaded connection in the machine that the internal reservoir hose is plumbed into, that the standard kit will likely have me replace. Did you plumb direct to that or is the reservoir line just a standard 1/4" that can be joined with push connectors?


#6: Post by PaulTheRoaster replying to espressoren »

I used the reservoir line. It's quite soft so I used a barb connector. Not sure a push-fit connector would work on soft tubing.

espressoren (original poster)

#7: Post by espressoren (original poster) »

Almost forgot about this thread but wanted to share my experience.

The reservoir stem is 3/8" it seems and fits a push connector perfectly.

However, beware that the internal side of this hose is quite loosely attached to a barb. I'm not sure it would withstand line pressure, especially when the machine is hot.

I ended up clamping this end to be safe. Interested in seeing what the official kit looks like, if it clamps to this barb or replaces the barb fitting altogether.

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#8: Post by ibetnoonehasthis »

How is this working out for you? Still running well?

I'm thinking of doing this setup this weekend.

espressoren (original poster)

#9: Post by espressoren (original poster) replying to ibetnoonehasthis »

Good timing! I was just about to do a post. While the above has worked fine for now, I don't see the official kit coming out any time soon and the 55PSI rating on the PVC tubing is really not ideal, so I switched it to a PU beverage tubing.

This tubing is rated at a massive 200PSI @ 160°F, compared with the PVC rating of 55PSI @ 70°F and is very flexible. It's the same stuff used for soda guns in bars. Much more confidence inspiring. It doesn't contact anything hot on the internals, either.

This is the 3/8" OD reinforced polyurethane tubing. Just make sure you get the food grade, other versions can leave off flavors in the water. Also used a stainless elbow, 3/8" push fitting on one side and 1/4" NPT on the other. ... ane-742U27

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#10: Post by ibetnoonehasthis »

Looks great!

Do you have a link to the fitting you used?

And just to clear it up in my head, it was a push on fitting on the barbs of the machine to a push on of the 3/8 hose, correct?

Thanks for paving the way!