Hi Ray I bought the power supply from Openlab in Perth, when I plug in the micro usb power supply into the PI; the PI fires up and the green light on the opensprinkler board lights up, which indicates that the opensprinkler is working. I have not checked the power supply to see if the transformer or the connector.
Let me see if I can clarify my reference to 2 systems I have 1 opensprinkler setup (with extension board) that is intended to control the sprinklers (a normal installation of opensprinkler), the 2 system I spoke about is a electronic float in a tank, connected to a relay, energized directly from the 24V transformer and the other side of the relay opens a solenoid with a with a connection to the common wire and pump start. I can create a diagram or take photos if that helps.
So what happens the float drops and the solenoid opens and then the pump start is triggered and the tank is filled, without turning any of the sprinklers on. Of course if the sprinklers are on and the tank solenoid is opened the pressure drops on the sprinklers until the float closes again.
The Opensprinkler has been removed because I was traveling and I needed to enable the tank to be filled.