Hey KanyonKris, and Alan,
Thanks for the advice, and info. I tested out the valves today by directly applying power, and it looks like they are NOT latching valves. On all but one of the valves I can hear the solenoid being held open. Unfortunately I think one of the valves will need to be replaced.
In any case, thanks again for the help and info. I’m going to order my RPi and OSPi today 🙂
Cheers!