I've just discovered that the West Marine rolling ball float switches
and the Rule 27D 1100 GPM (And possibly similar models) are not a good
combination. If mounted on a common base, the Rule does not draw the
water down far enough to reliably turn the switch off. It's a near
thing though. I have a dual set up. One works and the other doesn't.
A little motion from wake or sea seems to trip the switch off but you
can't always count on that.

I'm going to put a couple thick nylon washers under the float switches
which I am pretty sure will take care of the problem.

I've noticed that the rolling ball switches seem to need either a
little jerk or nudge or be at maximum travel before switching on or
off. Mercury certainly does work better but I hate to buy the stuff.

--

Roger Long