4. Hydraulic System
Tubing and fittings
* Virtually all of the fittings on the LaMarzocco are of the compression or flare type. Most are made
from brass, which will strip or crack if over-tightened.
* It is important when working with tubing not to bend or twist the sections you are working with, as
this will restrict the water flow or cause fatigue or leaks in the tubing.
Boilers & Groups
The La Marzocco uses hollow plated brass group castings attached to a stainless steel boiler on
machines manufactured prior to March 2003, and stailess steel groups welded to the boiler on ma-
chines manufactured beginning March 2003.
Below is a cutaway of a grouphead. Below the photo is the sequence of water flow through the
group to the portafilter.
1. Water exits the group head and travels through a tube to the flowmeter.
2. Water enters the flowmeter and rotates the impellor.
3. Water exits the flowmeter and travels through a tube to the group valve.
4. Water passes through the group valve...
5. And travels through a tube to the banjo tube inlet.
6. Water enters the banjo tube and flows to the banjo bolt.
7. Water passes through the banjo bolt and down towards the diffuser block.
8. Water passes through the diffuser block and enters the diffuser screw and screen where it
then meets with the tamped coffee in the portafilter.
1
2
3
4
5
6
7
8
*
In auto-volumetric models, the water from the group exits through a small tube on the left side of
the group and flows to the flowmeter, which meters the volume of the water. From the
flowmeter the water passes through to the group valve. From the group valve, the water
then flows back into a small tube inside of the group head and then to the diffuser block, the
diffuser screw, diffuser screen and finally to the ground coffee in the portafilter
