Bilge Switch setup

[dmksails]

My boat has a curious setup for the bilge pump. The pump is wired to 2 Rule-a-matic switches. One is about 6-inches off the bottom of the bilge. The second is about 8-inches below the top of the bilge. Both switches will run the pump.

I'm not able to understand the reasoning behind this. If the second switch is backup to the lower one, then why is it so high up?

Maybe this higher switch is meant to be wired to an alarm? (Its not)

[Dsanduril]

Not a fan of the Rule-a-matic switches as they seem to have a pretty short life. And jam easily with small debris in the bilge. I'm guessing the PO of you your boat found the same thing, so put in a second switch at the "oh s**t" level just in case the lower switch didn't start the pump as it should.

Better solution is probably to get a better switch. Lots of people here like the Ultra, I haven't used one so can't comment. Personally I use some industrial switches from a supplier I use regularly in business.

[Cheechako]

It's likely because the lower switch would cycle off/on a lot especially under sail. So they added the higher one for when sailing. Although why that high is a question.
The Ultra are great switches.

[Shrew]

IMHO that is an odd setup. The bilge pump should have two positive leads. One is to a float switch, the other to a manual switch on a panel.

I've seen where there are 2 bilge pumps a smaller pump with a float switch located lower, then a second significantly larger pump with a switch mounted higher. IF the smaller pump is overwhelmed and water continues to rise, the higher switch actuates the larger emergency pump.

It seems almost like the PO looked at 2 float switches at different heights, then looked at the two leads on the bilge pump, shurgged and hooked them together.

[bstreep]

It's not odd at all. As Dsanduril said, it's because Rule switches suck. They used to use mercury, and they worked great. Like everything else that was once good in boating, the product is crappy, and probably made in China. The solution was to put in 2. If the lower one failed, then when the bilge depth got really high, the second one kicks in.
Have a similar setup on our boat. But it's both a switch and a pump at the higher level. Redundancy.

[Flatswing]

Many boats have a high & low switch - but not wired like you describe. Typically the higher switch is wired to an alarm buzzer/warning light to indicate high bilge water - i.e. the main switch/pump has failed. Perhaps someone got the wires mixed up?