Soooooo, is the TLDR that with the Micra:
- you can set it to pre-infuse in the app even if unplumbed
- the machine continues to operate just fine
- there is no low water warning so you have to keep an eye on it, but it's not a danger to the machine
- the pre-infusion improves shots (how if so)

That correct?

Zoobee wrote:It's really annoying that they disabled it like this and I hope they will change that in a future update but speaking with LM tech support it seems unlikely they will because for some ridiculous reason "they don't really want reservoir users doing preinfusion". With the preinfusion on I've been able to brew excellent espresso from light roasts using the reservoir but I'm terrified of forgetting to check the water level myself. Totally lame to hobble functionality like this imho.

I would say start a thread about it so it's visible at the top level, link to it from the Mini user thread to build visibility, and have people lobby Chris (and maybe Dave too, not sure if appropriate, but he is a forum user and may be reading this) at La Marzocco to support preinfusion from the tank. Many users can't indeed plumb their machine, myself included, but would love preinfusion. I'm too scared to have no water sensing capabilities as I regularly hit "no water" right now. I don't think proactively watching the level would work for me, nor should I need to have...

NewCoffeeGuy1 wrote:Soooooo, is the TLDR that with the Micra:
- you can set it to pre-infuse in the app even if unplumbed
- the machine continues to operate just fine
- there is no low water warning so you have to keep an eye on it, but it's not a danger to the machine

The TLDR biggest danger to the machine seems to be:
if you run out of water mid-shot the machine won't stop and you will damage your machine.

Original post:

So I just tested pre-infusion on my LMLM running off the reservoir, and although you can enable PI in the app, no water comes out the grouphead. The timer starts in the app, but nothing comes out of the group for the pre-infusion time you set in the app, then the pump ramps up to full pressure. In my experience with the LMLM, there is no functional PI available on the machine running off the reservoir, even though you can enable it via the app.

Pre-brew on the otherhand works flawlessly, which will run the pump for a defined time at 3-bar, then shuts the pump off for a defined time, then ramps up to full pressure.

EDIT 1: removed 3-bar comment, I was remembering text from the app screen and confirmed that 3 bar was an example given in the pre-infusion section, not a spec for pre-brew. I don't know what the pressure during pre-brew is.

EDIT 2: Thank you Jaroslav and Zoobee for the comments and input, I was wrong. The LMLM does indeed have PI as long as you power the steam boiler on and let both boilers reach full temp. I usually only turn on the espresso boiler, since I don't make a lot of milk drinks. My original post outlines that behavior: if PI is enabled in the app and the machine is up to temp with only the espresso boiler, then there will be no pre-infusion, and the pump will turn on after the set time. The steam boiler needs to be on for the machine to generate the pressure used for PI. Sorry if this has been discussed before. I read a lot about the machine before buying it, but apparently not enough!

bbeaton wrote:So I just tested pre-infusion on my LMLM running off the reservoir, and although you can enable PI in the app, no water comes out the grouphead. The timer starts in the app, but nothing comes out of the group for the pre-infusion time you set in the app, then the pump ramps up to full pressure. In my experience with the LMLM, there is no functional PI available on the machine running off the reservoir, even though you can enable it via the app.

Pre-brew on the otherhand works flawlessly, which will run the pump for a defined time at 3-bar, then shuts the pump off for a defined time, then ramps up to full pressure.

How did you measure the 3bar pressure while using pre-brew?

My mistake, good catch I'm sorry I mis-remembered the text in the app. I edited my reply to reflect that.

removed 3-bar comment, I was remembering text from the app screen and confirmed that 3 bar was an example given in the pre-infusion section, not a spec for pre-brew. I don't know what the pressure during pre-brew is.

bbeaton wrote:My mistake, good catch I'm sorry I mis-remembered the text in the app. I edited my reply to reflect that.

No worries! That would be nice though.

bbeaton wrote:In my experience with the LMLM, there is no functional PI available on the machine running off the reservoir, even though you can enable it via the app.[/b]

I feel like this remains a key differentiating factor between LM (Mini or Micra) vs a flow controlled E61. Assuming you aren't plumbed in (which I gotta believe is a majority of regular home baristas (not the folks who frequent this board)), do you rely on LM with its saturated group head, or do you use flow control to optimize your preinfusion and pressure profile?

It's still a nearly $1k difference between the Bianca and Micra.

bbeaton wrote:So I just tested pre-infusion on my LMLM running off the reservoir, and although you can enable PI in the app, no water comes out the grouphead. The timer starts in the app, but nothing comes out of the group for the pre-infusion time you set in the app, then the pump ramps up to full pressure. In my experience with the LMLM, there is no functional PI available on the machine running off the reservoir, even though you can enable it via the app.

Works fine for me (2021 LMLM). Water comes out of the grouphead during the preinfusion period. Not sure why yours is different.