Alright. Long story short. I purchased a machine that originated from an Intelligentsia from Chicago. Even though the seller was VERY responsive, he just did not know enough about machines (little to nothing) to offer up any technical information. I normally would be hesitant about making a purchase under these circumstances, but it was a Mistral. I had to have it.




I just received the machine a few hours ago and have yet to turn it on since I like inspecting the internals for anything that might have been jostled loose, spot any obvious leaks and or any other potential problems.

First things I notice are just a few cosmetic issues like missing screws, missing rubber feet, and cracked plastic on the groupheads which I hope to replace with wood.



So, now comes my favorite part. Popping the hood. This will be the first time I have gotten the chance to explore the internals of a La Marzocco Mistral. I know they are mostly Linea and GB5 internals, but I have heard some were customized far beyond those machine specs.

Imagine my surprise when I saw this.




Each grouphead has its own boiler. Score!!



Ok. Open up the side panels.

Left side (when facing the machine).



Right side.



No obvious leaks and everything seems to be in place. I am still quite new to espresso machines so please, if anything seems out of place, let me know!

A couple things I'm confused about:

1)





Is that just a boiler drain line? The line on the farthest left seems to be the water inlet. The middle is the backflush outlet and empties into the drain tray. Not so sure what the one on the right is.

2)

What is this line going into or out of the group head?



3)

I'm not sure if this is the "prototype" paddle group that Paul Pratt mentioned in my last thread, but this cover assembly and some of the fittings do not look familiar to me.









Any help on the above would be appreciated! Thanks!

Sebastian

****4/16/2015****

I reached out to a few contacts at La Marzocco and received some prompt replies and answers.

1) As seen in the diagram below, the tube labeled #15 is the discharge tube for the groupheads. The block labeled #1 is the inlet manifold.


2) Answered by EricS in the comments. They are the electrical leads for the brew switch inside the groupheads.

3) The groupheads are indeed prototypes and a few fittings are different from the current ones being manufactured. I have to either fix the black bakelite (?) covers myself or replace it with wood. Mike from La Marzocco referred me to Dave Ringwood at Espresso Parts for custom wood options specifically treated for high heat applications.

Some things I learned from my conversations with Mike:

1) He doesn't come across Mistrals too often with this degree of sophistication.

2) The brain box is either a custom hybrid model or a GB5 with a custom flashed firmware. Either way, he said to be very careful and to take care of it. *sweat*

Anyways, on to more inspections.

I drained my steam boiler with my highly developed and patented apparatus.



I then unscrewed the pressure relief valve to gain access to the boiler for inspection. Fired up the endoscope to take a peak and held my breath...



Nice! Little to no scaling! Elements look great and the walls look nice and clean.

Great project! I hope you can get enough info to figure out what is what inside that beauty.

What is this line going into or out of the group head?

It can only be the electrical leads to the brew switch inside the group.

Ah, thank you Eric. Helpful as always.

Any ideas on the other items? I sent an email off to La Marzocco this morning and I'm just waiting for an answer.

FotonDrv wrote:Great project! I hope you can get enough info to figure out what is what inside that beauty.

Thank you! I will definitely try my best. I hope I can do this machine justice.

If that was a boiler drain line there would have to be a shut off valve. Is the other end just laying loose?

Yeah, I couldn't find the shutoff valve, so that's why I didn't immediately assume it was a drain line. The other end was just laying loose.

Despite needing a clean.. that machine is super sexy.. do you know if anything *serious* is wrong with it? Would be super awesome if you got out of the gate with minimal rebuilding. Forgive me if I missed this, what year is the machine?

With the paddle groups.. is there anyway to mod them to a pressure profiling MP like the GS/3/Strada? Or would this be too old to perform necessary mods? Speaking of which, I hope to see LM start to include pressure profiling in all of their paddle machines...

Hey Luke. The machine was built in February 2008. The serial number plate is nowhere to be found though and the serial number is also missing from all the manufacturing stamps on the frame and boilers.

As for anything being seriously wrong with the machine, I'm keeping my fingers crossed. I will have a better idea when I fire the machine up tomorrow.

The strada mod is definitely possible. These groupheads aren't that different internaly. I'm going to hold off on it though. I have enough on my hands and I don't want to get ahead of myself.

I wish there was more "evidence" if you will from it's Intelly days. For an Intelli machine, the only thing that possibly sets it apart (aesthetically) is the black (or that's how it looks) drip tray.

I'd be super stoked if you got those group heads converted.. talk about a seriously maxed out Strada. I hope the dual brew boilers work out!