Bilge pump control

[ghostlymoron]

I'm considering using a pressure switch off a washing machine as a level controller for my bilge pump. These have a diaphragm which operates the contacts and would have a dip pipe into the bilge. There seem to be several advantages over a float switch for a deep bilge .
1. Can't get crud stuck under float preventing switching off
2. Can't get stuck down by objects dropping on it preventing switching on 3. Accessible from above water level when bilge full.
Are there any drawbacks?

 

[nigelmercier]

I'm considering using a pressure switch off a washing machine as a level controller for my bilge pump... Are there any drawbacks?

Great idea, the pump will switch on when there is 30cm of water!

 

[Davegriff]

Only problem I can see may be the amperage rating of the switch. 4-5 amps on 12 volts DC is a heck of a lot harder on switches than 240 volt AC. (Or is it a DC switch anyway)

 

[prv]

Only problem I can see may be the amperage rating of the switch. 4-5 amps on 12 volts DC is a heck of a lot harder on switches than 240 volt AC. (Or is it a DC switch anyway)

Can always add a relay to the system if load is a problem.

Seems like a good solution to me (and I have heard of others doing the same) provided that the level it senses at isn't too high (as Nigel points out).

Pete

 

[NickRobinson]

Great idea, the pump will switch on when there is 30cm of water!

The washer switch will trigger with only 5/6 cm.

I used this set up on my last boat. When I tried one at home, it took more than 30cm, just pushing the thin pipe under the surface. Is this what you tried?

You need a plenum to increase the volume of air pushed up the pipe. I simply used an inverted 250cc plastic bottle with the pipe introduced through the neck to avoid piercing it.

No relay used, worked for three years on quite damp boat.

Nick

 

[rogerthebodger]

I'm considering using a pressure switch off a washing machine as a level controller for my bilge pump. These have a diaphragm which operates the contacts and would have a dip pipe into the bilge. There seem to be several advantages over a float switch for a deep bilge .
1. Can't get crud stuck under float preventing switching off
2. Can't get stuck down by objects dropping on it preventing switching on 3. Accessible from above water level when bilge full.
Are there any drawbacks?

Jabsco do one that works that way and is designed to drive electric bulge pumps

 

[ghostlymoron]

Jabsco do one that works that way and is designed to drive electric bulge pumps

Might experiment with Hoovermatic version first. Jabsco version £35 (not unreasonable)

 

[ghostlymoron]

Great idea, the pump will switch on when there is 30cm of water!

Nigel, 30 cm no prob in deep bilge. Have to check cut off level though.

 

[lw395]

I've always suspected that the slightest microscopic leak in the air space in the switch would stop the switch working, as the bilge filled slowly.
It's different in a wshing machine where the water gets lashed in in about 20 seconds.

Also how do they cope with atmospheric pressure changes?
I suspect they may have a tiny vent to cope with this?

What is so hard about making a float switch work?
Or something solid state that works on the conductivity of the water?

We use float switches on open keelboats. They usually last a couple of seasons of hard use. I can't expect washing machine parts to do any better in a marine atmosphere.

 

[pampas]

Two things are important.
1 you need a volume chamber in the bilge. about 2" bore and a pipe outlet to suit say1/4" pipe. cut two slots about 1/8" where it sits to allow water in.

2.assemble the whole system to include the total length of pipe work. use the heavy duty connection (Rated about 2Kw), battery + test lamp in series across these terminals and a bucket of water.

Lower the vol bit to the desired level at which you want the pump to cut in and adjust the wee screws to that level.

Remember you may have to raise the vol chamber base to slightly more that the slots in the case of your pump.

Very reliable system and cheap. have used this about 10 years now , the occasional peek to clean the volume chamber is all that is required

 

[NickRobinson]

Two things are important.
1 you need a volume chamber in the bilge. about 2" bore and a pipe outlet to suit say1/4" pipe. cut two slots about 1/8" where it sits to allow water in.

2.assemble the whole system to include the total length of pipe work. use the heavy duty connection (Rated about 2Kw), battery + test lamp in series across these terminals and a bucket of water.

Lower the vol bit to the desired level at which you want the pump to cut in and adjust the wee screws to that level.

Remember you may have to raise the vol chamber base to slightly more that the slots in the case of your pump.

Very reliable system and cheap. have used this about 10 years now , the occasional peek to clean the volume chamber is all that is required[/QUOT

E]

It's no good Pampas, (see my post 5) they're not listening!
They work though, don't they?
Nick

 

[nigelmercier]

Nigel, 30 cm no prob in deep bilge. Have to check cut off level though.

Blimey, I get paranoid if I've got 3 cm!

Having see the volume chamber idea, I can now see how this could work.

 

[Frankie-H]

QUOTE>.After six failures of various commercial units, I built my own. Then I built two more for friends. The oildest is now more than 3 years old and still working fine. PVC vertical tube. Internal connical foam float with small weight on the bottom to act as return and a magnetic switch (no contact neccassary, and no metal exposed to water). The float rises a couple of inches and the mag field activates a relay (the weak point as I see it, but one completely in the dry of the breaker box). Relay activates the pump.

I had an idea about adding a small mast to the float with a second mag-spot and a second mag sensorfurther up the tube. Float rises slightly, bottom pump comes on, float rises more, both secondary and primary pump activates as both mag sensors line up...Have not tried that one yet.

The nice thing about the mag switch is that there is nothing to corrode or leak away or for the pivot point to clog or corode...and all the other things that go wrong with standard units.QUOTE

I came across this on sailnet, with thanks to Sasha. Wondered if it might help.

 

[prv]

Jabsco do one that works that way and is designed to drive electric bulge pumps

I have visions of pants with inflatable chambers built in, designed to enhance the appearance of one's assets. Since putting a hand in the pocket and working a manual pump could easily be misinterpreted (especially given the result!) a remote-controlled electric bulge pump would clearly be vital

Pete

 

[rogerthebodger]

I have visions of pants with inflatable chambers built in, designed to enhance the appearance of one's assets. Since putting a hand in the pocket and working a manual pump could easily be misinterpreted (especially given the result!) a remote-controlled electric bulge pump would clearly be vital

Pete

Well a vacuum pump with the inverted bell from the jabsco bilge switch fitted to the suction inlet could also be used to give some one a little excitement.