"Roger Long" wrote in message
news
Does anyone have any experience to report with the new solid state
bilge pump water sensors such as the Johnson Ultima? Sounds like a
good, no jamb, no cog, idea to me.

The Johnson switch appears to have only two wires and go in series in
the circuit. I'm durned if I can see then how it gets the power to
run its little brain when the pump isn't running

If the switch is off there is 12 volts accross it as the voltage drop
accross the pump motor further down the circuit(while it isn't running) is
virtually nil. As the switch uses only a tiny bit of power, the switch thus
sends a tiny bit of power through the pump at all times, but so little the
pump motor doesn't move. Many electronic home thermostats work this way,
they call it "power stealing." Make sense?

unless it has a
little rechargeable battery in it some place. If your boat was really
tight and sat for a long time with dry bilges, could the switch then
go to sleep and not turn on if water got in?

I like the time delay feature. We have a wide bilge sump and, with
run back from the hoses, could end up with short cycling when the boat
rolls.

--

Roger Long



--
Ken Heaton & Anne Tobin
Cape Breton Island, Canada
kenheaton AT ess wye dee DOT eastlink DOT ca