All this to avoid a check valve?

"Roger Long" wrote in message
...
Here's a non electronic way to skin the cat discussed in the "See Water
bilge switch report" thread.

In order to have a longer ON / OFF range than provided by common level
switches, put a standard float switch in a coffer dam of the height you
want to start the pump. Put one of those valves used in anti siphon loops
in the bottom. The bilge will fill until it overflows the cofferdam and
the float switch will turn on the pump. The cofferdam will empty out
through the one way valve with the bilge and the float switch will go off.

This would also prevent surging water from burping the pump in a seaway.
You might need a pretty clean bilge to keep the valve from plugging up.
OTOH a screen across the top of the cofferdam would probably keep things
clean enough though. It would also protect the float switch.

Damn. I like this idea! Much simpler wiring. With our large flat bottom
sump, I've got to build the cofferdam anyway to avoid the surge problem.
Saves forty bucks of additional float switches. What's not to like?

The one way valve is the key thing. It has to let the water drain out
through 3 to 4 inch head but seal tight as the bilge fills. I just bought
a siphon break for our head. I'll fiddle with it and see if these easily
available and replaceable valves are the answer.

--

Roger Long