The Espresso Machine Restoration site
A non-commercial site for those interested in espresso equipment repair and restoration.
||La Marzocco GS Manual Group
The frame was obviously the first thing I had to complete so that I could then start putting all the parts back together
once they had come in from the various contractors. The frame took around 3-4 days to do properly and since it
was so small I could take my time and get a first class job.
I don't have any pics of the frame itself to show you so let me talk about the boilers. Ahhh the damn brew boiler.
Even now I grimace in pain at recalling the struggle to get the brew boiler and group together.
As I have explained many times on my little site, the old style La Marzocco brew boilers are not the easiest of things
to work on at the best of times. You have 8 brass nuts suspended inside the boiler and then you have 8 steel
screws that fasten the group to the boiler. Tighten the screws inside the nuts and you have done your job. It sounds
simple enough, however you cannot actually see the nuts once you put the group on the boiler and the only way
you know you are in the right spot is by "feeling" that the screw has mated properly and that you haven't just
cross-threaded the screw. Remember 1 cross-threaded episode means 1 broken brass nut and you must start all
over again by removing all good screws, the group, the cage, the nuts and a new gasket.
Usually I don't have much trouble with this fastening system. We are probably looking at 20 mins per group if I take
my time. This time 1 group, 1 boiler took over 6 hours! So I came into work on a Saturday because I was so
excited to finally see if the manual group would work. I hadn't even contemplated that I would have a problem
attaching the group to the boiler.
The problem was of course the ice damage which had warped the boiler. Even though my buddy Mr. Lee had
repaired it for me it was still not back in it's original shape - not even close. That meant that the 8 holes on the
group didn't match the position of the 8 holes on the boiler. The cage and boiler was ok because you can get the
nuts to wiggle a bit so that gives you some leeway. After trying twice I resigned myself to the fact that I was going to
make further adjustments to the boiler - I had to drill out the holes so that they aligned with the holes on the boiler.
So I did it a little at a time, each time having to wash the boiler free of any cutting fluids, swarf etc....
Then 6 hours later it went on. In the process I broke 4 of the brass nuts having successfully damaged the threads
inside. Excuse the terrible photo below, but under mains water pressure it worked!
I have to admit, I did fear the worst. I even began to draw up a shopping list to fabricate a new boiler. Then when I
finally got the last screw to "bite" into the nut I almost wept. Then it was just a case of gently tightening each nut in
sequence so the group would seal with the boiler.
You can also see in the pictures to quality of the work the plating company did. On the original group only the
exposed part of the group has been polished and the back half is crude and ugly. The plating guy removed all
bumps and presented me with that.
Once I had the boilers done I could then start putting it all back together. The way the machine is designed is so
that you have to put the boilers in first before anything else can go in.
Getting the boilers back in was easy. Once they were in I could then start to plan the wiring layout.
The original wiring was bad in terms of safety and condition. So I decided it was again time to adopt the "linea"
system and use current La Marzocco models as the base. The machine has two main cables, one for the power and
the other to the external pump.
Also it was time to remove the manual thermostat and put in place a PID controller. Now don't panic, all the
upgrades are easily undo-able and we can have the original specification machine back with ease.
It turned out to be a long drawn out process. Because the pipe network is so small and intricate I had to put the
pipes in then see what space I had to place the autofil control box, the PID controller and the Solid State Relay that
controls the brew boiler element.
|The rebuild continues on page 3
|This website is created by Paul Pratt, Hong Kong 2004-5. If you would like to use any of the images or text I am sure
I will say yes, but please ask first!
Email me here.
|The first switch on.
It's always a nerve-wracking experience flicking the power on for the first time. Then you hear the autofil kick-in and
see the water fill the sight glass. Magic.