The group is only heated by the flow of water in and out via thermosyphon as indicated here:

Conduction from the thermosyphon circuit heats the entire group.

Water for brewing is taken through the channel from the thermosyphon circuit into an annulus around the group sleeve and distributed to the portafiler through four holes in the side of the sleeve:



I doubt the grease impacts heating the group. It probably doesn't affect the distribution of water to the portafilter either since the water is under ~1bar pressure (for most machines).

I think I understand the waterpath shown in red, but the blue path in the second diagram stumps me. As this is the same neck shown in the image above, how has the physical shape of the water path changed?

The first image is for thermosyphon heating and the second is where the group is attached to the boiler for heat transfer. Both are CMA groups but with different group heating.

nah my thermosyphon is working fine.
just that i find the design very weird when comes to heating of group through thermosyphon.

chappcc wrote:The first image is for thermosyphon heating and the second is where the group is attached to the boiler for heat transfer. Both are CMA groups but with different group heating.

Thanks.

First (red) shows thermosyphon configuration, second (blue) shows dipper configuration with the check valve

So, the first (red) represents the Londinium group and the second (blue) represents the Bosco group. All clear now. Thanks.

Matt

Thanks for those diagrams and the explanations. Very interesting. I recognize the blue one from Dan's review of the Profitec 800.

I had not paid attention to realize the Profitec was a Dipper, like the Bosco! Pretty nice.

Thanks for those 2 diagrams.