The 500gph Rule bilge pump in both of my boats has been a non float type. I believe it cycles every two minutes or so and pumps til there's no water left. On the pump, there are three wires, a brown (on all the time) a brown with black stripe (cycle) and a black (ground) THe brown lead was not used on my millenium dash boats, kind of redundant. I don't know how it works, but it pumps when there's water and stops when it's gone.
There was nothing to hooking up the new one but splicing two wires and hooking up the hose, clip it into the original holder if it's not broken.
I have been working the hell out of mine lately, till I found my leak. I had the shower pump off but the panel knobs were wide open and it was seeping:0

I'm sold on Rule pumps, they are cheap as sheaot and they work for a long time.