As a new user of the forum, my best regards :-).
My problem: VHP valve. From the tube from port 4 leaked very very slowly, one drop every few minutes. I cleaned the rotor and stator, screwed the valve head on - evenly, slowly to the first resistance until the head rested on the valve base - exactly as described in the manual. When I started it for the first time, I heard "wrrrr...." and an error popped up. I unscrewed the screws 1/2 turn, the valve works, but the leak remains.
I would ask for practical comments if there were any problems described above after replacing the rotor seal.