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Remember you're a womble
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Discussion Starter · #1 ·
Went to the boat the other day and the bilge had water in it. Turns out the wiring that goes through the float switch had blown a fuse. I replaced the butt connectors in the bilge and put a new fuse it and it seemed fine. I was there today fixing up some other bits and bobs and noticed that when the bilge pump is operated manually, it pumps just fine but when it operates via the float switch, it doesn't seem to be able to pump properly - turns but doesn't really pump anything out and likely was the same after my "fix" previously.
Basically looks like when it is running via the float switch the pump is not able to draw enough current.
It's an old Rule float switch in there, mercury job from what I can tell. Also, when you run the pump for a while via the float switch, the wire from the switch starts to heat up so clearly there is some resistance in the circuit. Is the float switch on the way out and starting to cause problems? When I tested it previously it had almost no resistance when engaged. Alternatively, is it likely a wire has suddenly started to degrade?
Should I just replace the switch?
 

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I've got a box of mercury switches. Wires frayed ,corroded ,upgraded the whole unit ,etc .Time to start your own collection.
 

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Remember you're a womble
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Discussion Starter · #3 ·
Thanks Len, I'll swing by WM in the morning and pick up another switch. Hopefully a simple fix (famous last words).
 

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Buy a better switch. The Whale or the Waterwitch switches are reliable and have no moving parts.

Whale: Whale Marine - Products

Waterwitch: https://www.waterwitchinc.com/new/SiteElements/Pages/SecondaryPages/Products/BilgeSwitches.html

I prefer the Whale as it is smaller.

Having said that your problem may be a bad connection. Switches in my experience either work or they don't. It's possible that you have a connection that is either corroded or bad. If only a strand or 2 are making a connection the pump will probably turn slowly but not enough current can pass to run it properly. I would check or renew all connections in the float switch side.
 

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With a wire heating up as you describe, I'd say the problem is in the wire or connections. There shouldn't be that much resistance in properly sized wire. That's what I would think needs to be replaced.

Tod
 

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Remember you're a womble
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Discussion Starter · #6 ·
I re-did the connections already so they should be OK, and the wire that heats up is the wire coming from the switch itself so there's no way to replace that. Clearly the problem must have existed in some way previously as it blew the fuse in the first place - that's why I went and redid all the connections in the bilge. Of course there is always the likelyhood that my re-done connections are rubbish.
 

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Here's a way to test:

Disconnect pump from switch. Get a bunch of wire same size as in there. Temporarily run it from switch to pump and turn on switch and activate pump. If that wire gets hot, the problem is somewhere else (bad pump, float switch, etc?). If it doesn't get hot you can surmise that the problem is in the wire, etc. you might have a short due to abrasion in the wire that you can't see. It only might happen in rare occasions. But a short can start a fire and fires do not belong on a boat.

Tod
 

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Remember you're a womble
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Discussion Starter · #8 ·
It's this wire that gets hot:


Switch panel is the standard OFF/MANUAL/AUTO type with a 10A fuse, also a 10A fuse between the float switch and the switch panel.
Note that I didn't install this. I need to get this sorted as at the moment I don't have an automatic pump in there, not going to run the risk of the wire burning (which it will).
 

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Which size pump do you have? 9 amps is the recommended fuse for a Rule 1500, any pump smaller needs a smaller fuse:

1100 - 6 amps
1000 - 5 amps
800 - 5 amps
500 - 2.5 amps
360 - 2.5 amps

The larger pumps need larger fuses starting with the Rule 2000 at 15 amps and then going to 25 amps for the 3700 and 3800.


I also think it is a connection problem.
 

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Remember you're a womble
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Discussion Starter · #10 ·
It's a 1500. The original fuse between the panel and float switch was 7.5A, and the switch panel had a 20A installed! The closest I had to 9A was 10A, which I figured was better than 20A.
I guess I will go and cut out my connections and make a temporary one instead and see if the problem goes away. If it does then I'll remake everything again. Those Ancor adhesive heat shrink butt connectors aren't cheap.
If the connections aren't at fault, it could only be the wiring from the switch panel to the float switch, or the float switch itself?
 

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It could be either, that's why I suggested to run a seperate wire between the float switch and the panel switch to rule out one or the other.

Tod
 

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Remember you're a womble
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Discussion Starter · #12 ·
Cut out a connector and just twisted the wires together and it seemed much better. Replaced that connector, not sure why it didn't connect well originally but there you go. Onto the next problem :)
 
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