Thanks for the clarification.
I actually was planning to have a front-end to the OSPi. I would have a toggle switch for each valve exit in order to allow its use automatically or overriding it to manual.
A led Green will light up in case the valve is commended in automatic and a led red will light up is the override was selected.
In this set-up I will get as input the 8 valves wire plus the common. I will need however the other AC wire . would it be possible to get it from the EXTOUT connector ?
Which one would it be ?
I enclose a schematic (very preliminary to illustrate the concept)