Automatic bilge pump (or switch) with large working range

[JumbleDuck]

My bilge is pumped out from a sump in the long keel. It's quite small, though deep, so by the time the Rule automatic pump has filled its discharge pipe the sump level is almost low enough for the pump to cut out. The result is lots of short runs (five seconds every ten minutes) which waste electricity without doing much useful pumping.

I'd rather avoid the extra back pressure of a non-return valve by the pump, and access is in an case rather restricted because the sump is, as I said, small and deep.

What I'd really like is a pump, or a switch, with a much larger range between "switch on" and "switch off". At least three inches, and perhaps even six inches - which is still only a gallon or so.

Bright ideas and recommendations eagerly sought.

 

[pvb]

You could achieve this easily with a relay and 2 float switches (or solid state switches).

 

[NorthUp]

Two floatswitches (high / low level) and a double pole relay.
The float switches make contact at high water, the contacts used on the relay are ganged together, diagram shows the low water level position.
The pump will not operate until the upper float activates, then will run until the lower float opens.
Add fuses as required!

 

[superheat6k]

I fitted one of these last year. Seems to have a reasonable overrun period, and won't lead to galvanic current leakage.

http://www.force4.co.uk/7588/Whale-Electric-Field-Sensor-Switch.html

 

[pvb]

A rather simpler solution...

 

[NorthUp]

A rather simpler solution...

....and much neater drawing!
My only excuse, my original was for a 110v pump with 12v sensing, sketched from memory in a hurry!

 

[VicS]

I fitted one of these last year. Seems to have a reasonable overrun period, and won't lead to galvanic current leakage.

Will it give the 3 to 6 inch range that the OP requires or will it suffer from the same trouble as his automatic pump?

 

[JumbleDuck]

Will it give the 3 to 6 inch range that the OP requires or will it suffer from the same trouble as his automatic pump?

Although it's an interesting idea, I don't think there is room in the sump for that switch and a pipe, or even a second strum box - the manual bilge pump works from there too.

 

[David2452]

Will it give the 3 to 6 inch range that the OP requires or will it suffer from the same trouble as his automatic pump?

The standard switch without time delay gives a two inch range so I would think the extra 30 second delay of the time delay model will do that, they have the advantage of ignoring "sloshing" too so only operate when there is actually some water is there to pump unlike mechanical ones, I have used a few in grey water sumps, shower sumps and bilges and quite like them.

 

[VicS]

The standard switch without time delay gives a two inch range so I would think the extra 30 second delay of the time delay model will do that, they have the advantage of ignoring "sloshing" too so only operate when there is actually some water is there to pump unlike mechanical ones, I have used a few in grey water sumps, shower sumps and bilges and quite like them.

Model BE9006 then. http://www.whalepumps.com/marine/si...ccessories-spares/elec_mag_switch_v5_0313.pdf

Not going to work with the existing automatic pump though I guess. Not possible to modify it to work with a remote switch I suppose ??

 

[pvb]

As I read it, JumbleDuck's problem is with the water in pipe running back into the small deep bilge when the pump switches off. It seems unlikely that a delay switch will prevent this happening, which is why he's looking for something with a 6" range between switch on and switch off. The only way to achieve that sort of range is with 2 switches and a relay, as I posted earlier.

By the way, the electronic sensors suggested may not work properly if there's any oil contamination in the bilge water.

 

[David2452]

Model BE9006 then. http://www.whalepumps.com/marine/si...ccessories-spares/elec_mag_switch_v5_0313.pdf

Not going to work with the existing automatic pump though I guess. Not possible to modify it to work with a remote switch I suppose ??

I would imagine so, even if its a simple bridge conductor to bypass the current activation method, an effective though probably not ideal solution if the OP wishes to retain the current pump though.

 

[JumbleDuck]

Not going to work with the existing automatic pump though I guess. Not possible to modify it to work with a remote switch I suppose ??

Easy peasy - the existing pump has "on", off" and "auto" settings, so a new switch could simply control the "on" supply. I shall investigate that switch, thanks.

By the way, the electronic sensors suggested may not work properly if there's any oil contamination in the bilge water.

One does not have vulgarities like oily bilges, my dear sir!

 

[VicS]

As I read it, JumbleDuck's problem is with the water in pipe running back into the small deep bilge when the pump switches off. It seems unlikely that a delay switch will prevent this happening,

Not clear what the 30 second delay delays. If it delays the switch off it might help .
I think you are right though. Standard model has a switch on delay of 10 secs. Time delay version has a delay of 30 seconds

 

[pvb]

One does not have vulgarities like oily bilges, my dear sir!

Guess you don't have a Volvo Penta with the oil filter fitted on the vertical face of the block then!

 

[pvb]

Not clear what the 30 second delay delays. If it delays the switch off it might help .
I think you are right though. Standard model has a switch on delay of 10 secs. Time delay version has a delay of 30 seconds

Yes, it's not clear from the literature what the delay means. Regardless, I don't think it'll solve the problem. My last boat had a very small, but very deep, bilge with a manual pump only. On stopping pumping, a lot of water would run back down the pipe into the bilge.

 

[JumbleDuck]

Guess you don't have a Volvo Penta with the oil filter fitted on the vertical face of the block then!

I have a 1GM10 with the oil filter on the front face of the engine ... and a tray underneath which neatly catches any drips or spills.

 

[fishermantwo]

Just buy a water witch and be done with it. I had the 101 model in my trawler and I see they have a 5 year warranty now, I thought it was a lifetime warranty when I bought mine. They are not effected by oil or anything else. They are expensive but by far the best bit of kit you can buy for your boat.

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