Blue Oak
Member
That one in the first url would be the correct thing to control the pump to control the pump that fills the tank . ("pump up")
The opposite kind as shown in the drawing, that empties a sump/tank, would be called a "pump down" type. That could also be the one that would be used in the cistern/tank to prevent a pressure pump from running when the cistern/tank is empty
You want one with "PU" in the model number, rather than "PD", to control the pump that fills the tank.
Hang on. The second link and image are found on the same page as the first link. I guess I'll just wire the thing up and test it upright then inverted.