Automatic switches

[colvic]

Has anybody used one of the Jabsco bilge pump switches that work off air pressure increasing in the switch housing as the water level rises in the bilges?

This system works in washing machines to switch off the water inlet valve, but a replacement switch for a washing machine is only £5 whereas Jabsco's switch retails at almost £50.

Looking for a reliable switch, so any experiences/comments greatly appreciated



Phil

 

[Breoch]

Tell me more about these washing machine switches

 

[pvb]

The reason they're more expensive than washing machine units is that boat switches need to cope with high current DC loads, whereas the washing machine unit can get away with cheaper contacts to handle the small AC currents involved. If you wanted to experiment, you could use a washing machine switch to operate a 12v relay to control the bilge pump - but you'd need to be careful about corrosion-proofing the connections.

Incidentally, GaelForce do an air-operated switch which will handle 20amps at 12v for about £35.

 

[LadyInBed]

A small bore tube runs up from the back of the drum to a plastic box containing two pressure switches. One switch is set to sense when the drum is full of water and turns the water off, the other senses when the drum is empty so the next cycle can start ie spin.
If the tube gets blocked with powder etc the machine will either over fill or more often not start its spin cycle or both. The remedy is to remove the tube from the back of the drum and poke out the sludge with a screwdriver.

What more can I say?

 

[tr7v8]

Personally anything that gets the pump connections away from the bilge is a good idea.
As regards using a relay I'd do that anyway as switches continually running on DC can't be a good idea so using a relay seems a good idea.
Their was an article on using washing machine air switches a little while ago in PBO, he remarked on how cheap they were. I was going to do this but didn't for 2 reasons, the first is that this area of the bilge is extremely inaccessable on my boat and secondly I brought a Rule 1100 Automatic pump off E Bay which doesn't use any type of conventional switching. All I have to do now is find a small child to install it.

Jim
----------

 

[bedouin]

I've got a pressure operated bilge switch - not sure if it is the Jabsco one or not, which cost about £20 (special offer) from LYC. I chose that switch because it is easier to install, and less likely to be jammed (open or closed) than the comparable float switches.

I found it easy to fit and it works very well.

 

[qsiv]

I use two sorts of switches on board.

Most (3) are electronic WaterWitch switches (Dutch I suspect) - they are totally reliable, phenomenally sensitive, and a little susceptible to oil contaminination (Oily water doesnt flow off the contacts as well as plain water).

The other switch installed last year is a Jabsco Air (24V rated), which also works very well. The tube is smallish in bore and will in due course be susceptible to choking if anything nasty (an emulsion perhaps) were to get in it. It is not so sensitive as the electronics, but costs about a tenth - so seems good value.

 

[LadyInBed]

I still prefer the basic float switch. It’s simple, cheap and with an On/Off switch wired across it, foolproof. It is also easy to test, raise the float arm and the pump starts.
On my last boat, I mounted it in a tupperware box with a hole cut in it and covered with a plastic mesh.

 

[HaraldS]

Had washing machine type switches for the bilge pump some 30 years ago. The switch never failed. We had a bell shaped part connecting to the little pressure hose and it needed some cleaning once and so often. Dirst can clog the entry hole but usually time overcomes any obstacle and all you may see is a delay of a minute or so. That is provided the upper part, hose and membrane, are really air tight.

The cheap washing machine switches are usually rated at 16A as they directly switch the heat elements. Usually that is plenty, but you can always add a cheap car relay if you need more power.

The metal upper part of the washing machine switch will rust unless you treat it.



<A target="_blank" HREF=http://www.taniwani.de>http://www.taniwani.de</A>

 

[polarity]

You can always use a piece of dowel with a cork on the end kept loosely in a plastic tube mounted vertically. Cork end in bilge, mount standard float switch above end of dowel. Water makes the cork float and so push up the float switch. All expensive electrical parts mounted out of the bilge! (is there was an attachment facility on this board for a pic?)

Paul

 

[maxi]

Have used a washing machine switch for the past 10 years with total success. The great thing is that it keeps electricity out of the bilge and has no floats to jam.
PBO carried a step by step article on setting-up & installing such a switch, probably 2/3 years ago.
It's a good idea to have a larger diameter tube at the bottom of the bilge, feeding into the small sensor pipe, this provides a more positive actuating force.
Maxi.