Float Switches who uses them?

[Binary]

I too was worried about draining the pond & killing the plants, fish, tadpoles etc etc.

I used this type, hidden under a rock
http://cgi.ebay.com.au/Float-Switch...ment?hash=item4cea1a022c&_trksid=p3286.c0.m14

Made up a circuit to turn pump off if level drops and keep it off as level raises due to draining of filter & stream - I didn't want pump to cycle off/on/off/on. On the event of power failure will auto restart the pump once power returns. Mounted the switch on a 90mm stormwater end cap on some 90mm poly storm pipe (cut to the cut-out height), rock on top and you can't see it

 

[newday3000]

Cool looks really small and easier to hide.

Do you have that much water in the stream and filter that would turn the switch back on?

The float switch I have is a mercury switch and the water would need to rise up several inches before it turned the pump back on. My filter drains backinto the main pond as well but it's not enough water to re-activate the switch

 

[koikeepr]

binary, how the heck does that little thing work exactly? Does it just push in? I've never seen anything like that. Fascinating.

 

[Binary]

As mine is very small (it has 5mm travel) there was a chance it may sence high water level once pump stopped and things drained back to the pond. This is why I made the circuit to not auto restart (excluding power failure)

They have a reed switch in the center and the float ring has a magnet. All the little ones I have seen have a E clip at the bottom so you can turn the float over - this allows you to reverse the switch operation - ie change the closed circuit when water high to an open circuit.

You mount them vertical, I did this inside some PVC storm water pipe with an end cap then rock on top. Just cut PVC to length, put end cap on, drill hole for float and bolt float on. Small holes drilled on PVC pipe & cap to allow water & air to escape. I'd take a photo but really im sure your not intested in a rock :biggrin:

Here are two more of the same type:
http://www.made-in-china.com/image/2f0j00haEtmWQzFTtJM/Plastic-Level-Switch-LSA-34-1-2-300-P-.jpg
http://www.maplin.co.uk/Module.aspx?ModuleNo=221982

You can get them all sizes and makes, I've seen ones at work that are stainless and about 2 foot long with an empty contact and full contact (Oil tank level).

If you are buying one take care of contact rating and think of your setup - mine goes via a relay to switch the 240V to pump so I can have 12VDC in the pond to the float, not voltages that could kill. As the leads are only short you will need to extend them (I just soldered then sealed with araldite) I was not going to do that with dangerous voltages.

 

[FredrikAnderson]

I have a RODI filter that takes my tap water and filters it before adding it to my pond. I have a float valve on the end of it so that it puts water into the pond when the level gets lower then the float valve. The filter will only allow 100gal a day flow. I can see how a pump shut off would be nice if the level got too low as well. I would probably have it set like 6 inches below desired level to make sure it only turned off the pump if there was a real problem happening.