Abdulaziz Yes, that basically it.
The easiest thing would be to find a 24V solenoid for the installed valve, but I could not find parts for it.
I bought this one:
https://www.aimfluid.nl/nl/artnr/0ae106bv35201/acl-magneetventiel-e106bv35-2-2-nc-g1-4-fpm-dn3-5-024-dc
It has ¼″ connections, so I needed adapters for it and I needed to drill new holes to mount it on the bracket. You can try to find a smaller ⅛″ model and use the supplied ⅛″->½″ adapter and hose. But I wanted a big enough orifice (3.5mm), but probably a smaller orifice will be sufficient, like a Parker N74.4 with 2.5mm orifice. https://www.parker.com/literature/Fluid%20Control%20Division%20Europe/5500UKLow.pdf
On top of the valve you need a connector to connect it to the manifold with 6×4mm PE tubing: https://www.pneuparts.com/en/item/SC184MSV
I took out the pump to create some working space.
On the manifold there is the same kind of connector (green circle). You can loosen that carefully and mount the new tube.
You can loose the t-piece (in red circle) that connects to the pump, and go directly to the manifold.
Take the wires from the pump and connect them to the solenoid. I use the yellow/green ground-wire from the original solenoid as well.
USE A PRESSURE REGULATOR WITH GAUGE ON YOUR WATER LINE!!!
I have line pressure just above P-stat pressure. When I pull down the lever, pressure will drop and solenoid will be engaged by the P-stat. When I lift the lever, pressure will raise and the P-stat will close the valve. 
I have some water in the reservoir, because the water level switch is still connected. Don’t know what to do with it yet.
The solenoid will also be engaged when water level is low in the boilers.
(How is the water level in the coffee boiler controlled?)
When the pump was still in the machine, I often heard a resonance when the pump was working. I thought the resonance was from the pump. But now the machine is pumpless, I still get the resonance when I pull down the lever and water flows through the system. It seems to come from the manifold. Does anyone know how to get rid of it?
