2 bilge pumps on one float switch?

swimmin' for shore

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Oct 25, 2004
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When it comes to lifesaving gear, like bilge pumps, I'm a fan of overkill. I have a 16' flat bottom sea nymph, and wanted two 500 gph bilge pumps rather than one larger one. I prefer the backup ti having a larger capacity single one. At any rate, can I wire them both to the same float switch, or do I need a 2nd float switch? I hear that bilge pumps go regularly, but I don't hear many complaints about the actual float switch, so I'm much less concerned with that going bad than the idea that I might overload something. Can anyone provide any guidance on this?
 

Boatin Bob

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Sep 24, 2001
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Re: 2 bilge pumps on one float switch?

I guess so long as the switch can handle the load current of both pumps on at the same time as well as all associated wiring and fuse. Actually I think I've heard more complaints about failing float switches or debris getting caught underneath and not letting it turn off.
 

xtraham

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Re: 2 bilge pumps on one float switch?

one switch will operate 2 pumps, I use a switch to each and every pump I have, if the 1 switch fails you have no auto pump at all, if each pump has it's own switch odds are you will have a working pump if any 1 of the components fail, in fact I have switched all my pumps to the electronic switched rule because of pump switch's that failed, and the electronic switched pumps don't surge when the boat rolls causing the pump to cycle
 

JB

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Re: 2 bilge pumps on one float switch?

Two pumps would draw twice the current. I think it is very unlikely that a switch sized for one would reliably carry twice the design current.

Use two switches for the reasons Xtraham gives.
 

Texasmark

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Dec 20, 2005
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Re: 2 bilge pumps on one float switch?

Agree with JB and Xtra. Also if one float operates 2 pumps, one may be submerged while the other is dry.

Never took one apart so don't know what happens to them when you run them dry. At the very least you have temperature involved and a sealed shaft turning out of any kind of fluid or heat sinking mechanism. Shooting from the hip I'd say that you would have pump reliability problems.

My 2c,

Mark
 

tashasdaddy

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Re: 2 bilge pumps on one float switch?

i also run 2 pumps, 2 switches, of separate batteries. on off the main starting battery, the other of the trolling battery. i also have an override switch on the trolling battery so the pump does not kick on while trolling. i activate it when docked, or emergency.
 

bruceb58

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Mar 5, 2006
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30,582
Re: 2 bilge pumps on one float switch?

If you are going through the trouble of adding a second bilge pump for redundancy sake, it is a no brainer to add a float switch to the second pump.
 

sailsmanship

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Jul 26, 2000
Messages
389
Re: 2 bilge pumps on one float switch?

One switch for two pumps does not provide a back-up in case the switch fails. I have had way more switches fail than pumps. Go with two pumps/two switches.
 

swimmin' for shore

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Oct 25, 2004
Messages
490
Re: 2 bilge pumps on one float switch?

Thank you all. 2 switches it is. And tashasdaddy, I love your idea about running to 2 separate batteries. I'll run the wiring for that when I wire in the 2nd switch. Thank you all again.
 
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