Join Date: Aug 2006
Location: Arlington, VA
Thanked 13 Times in 11 Posts
Rep Power: 11
Andre and Alex,
I feel your pain, having also tried most of the switch types on the market and with mixed success over a 25 year period. Also, from seeing dozens of customer vessels with their bilge pump switch problems.
The most reliable switches are generally considered to be those in the Ultimate Switch family. Not suprisingly, they are quite expensive. They are warrantied for 5 years, and users report amazing success.
Over the past ten years or so I've been using a succession of sensor switches...those which essentially are activated whenever water comes in contact with the sensors on the small units. Generally, these work pretty well, but only if you keep them really clean. If oil builds up on the sensors, you get flaky results, including a switch which fails to turn off. I run two of these all the time on my boat, and clean them periodically. Happily, I have bilge pumps which are not harmed if they run dry, which has occasionally happened when the darned little switches fail to turn off.
When I get tired of fooling with these inadequate devices, I'll probably spring for a couple of Ultimate Switches.