Installing float switch to bilge pump?

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hertel11

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My bilge pump currently only has 2 settings, On and Off. I would like to install a float switch to this bilge pump and am wondering if the current electric (SPST) switch would work and how to go about installing the float switch. I want a float switch because I can not see the bilge during normal operation without lifting a cover.
 

fhhuber

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The current switch can work fine.

The question is which of 2 ways you want to wire in the added float switch.

1: Float switch in parallel to the currently installed switch. The pump actuates automatically or by switch.
2: Float switch in series with the currently installed switch. The pump can only operate if the current switch is on and the float switch is triggered by water level.

For a boat parked on the trailer a lot, #2 is generally better as it protects the boat's battery. You're expected to check the boat occasionally to ensure the drain isn't clogged and rain water can't accumulate.

For a boat that spends most of its life in the water tied to a dock #1 is better.
 

tex599

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Wire in a 3 position switch, off, on or auto. That gives you the ability to switch bilge on without the float in the equation, in case you need too.
 

JASinIL2006

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Wire in a 3 position switch, off, on or auto. That gives you the ability to switch bilge on without the float in the equation, in case you need too.

I think option #1 in fhhuber's reply accomplishes the same thing (being able to turn on the pump manually) without adding a new switch. The only downside I see to his #1 is that there is no true "off" position, because in that example, "off" is the same as auto...

Personally, even though my boat spends most of it's life on a trailer (with the exception of a few weeks in the summer when we're at the lake), I don't want the ability to shut off the pump completely. I want it there, ready to empty my bilge if water comes into the boat. I don't want to be in the position of failing to note where the switch is and inadvertently letting the water level get too high; I want the bilge pump to come on without any intervention on my part, if needed. (I also want it to come on if I want it to....)
 

gm280

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I like the option to turn on the bilge pump any time I want but also have the option to have it in an automatic mode as well and still be able to turn it off. If I have the boat at home I don't need anything wired to pump water. I have the drain plug open at all times. And that drains water before it gets to any level. So that is just my $0.02 cents worth.
 

alldodge

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My bilge pump currently only has 2 settings, On and Off. I would like to install a float switch to this bilge pump and am wondering if the current electric (SPST) switch would work and how to go about installing the float switch. I want a float switch because I can not see the bilge during normal operation without lifting a cover.

Here is one setup (note it has a on/off/auto switch). Not the best to be able to turn your bilge pump off Bildge pump.gif


This is a good and also IMO typical for boat installs, (note this does not need the alarm, may have a light) but will only use a single on/off switch Bildge pump auto.jpg


Now with the above designs, are you sure you don't already have a similar setup with a float switch?
 
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Mike7jack

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Jun 13, 2023
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My bilge is already set up to the switch off and on at dashboard.

I want to add the float to existing bilge pump.

Not sure how to wire it, find the diagrams confusing.

Thx
 
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