I’m looking to develop an improvement to my existing home irrigation system.
Currently I have a master Solenoid valve on the mains water connection which Is opened by the irrigation controller whenever one of the watering zones is scheduled to run.
I want to have the option to feed my Irrigation system with Tank water via a 240v pressure pump. I had thought I would install a solenoid on the discharge of the pump, meaning that when I have tank water, the pump solenoid valve opens and the mains valves stays closed. Then when my tank level goes down, the pump solenoid would close and the mains valve open.
I had thought that I could add a SPDT relay with Common relay connection connected to master zone on irrigation controller, and then NC to the mains valve and NO to pump valve (with the common wires all connected back to the common port on irrigation controller.
The arduino would then flick the relay between NC and NO and activate the relevant solenoid depending on water levels in tank (and also default to mains for any power outages when pump couldn’t run).
My only concern is that as I understand the relay requires a constant signal to keep relay NO. I have tried to research the idea of a latching relay but haven’t stumbled across the solution.
Looking to get advice (pros cons and alternatives) to what I’m currently thinking. Any input would be greatly appreciated.