float switch

[funinthesun]

Hello!

I have a float switch like this one in a grey water holding tank.

It often sticks in either the open (not operating) or closed position and is a complete pain in the proverbial as when the tank overfills it backs up all of the basins/sinks. The float switch seems to get gunk on it or scale, this can only be cleared by inserting the whole arm and fiddling around with said float (not nice). The two wires on the outside of the tank connect to some sort of switch. Is there a way I could interrupt the circuit/wires and fit a button in an easy to operate location to override the pump when said float sticks? If I could do this at least I could pump the water out before inserting body parts to facilitate cleaning.

Thanks

 

[Refueler]

Of course you could.

All you need to do is basically short across the two wires of the float switch via a push button or toggle switch.

My Bilge pump has float switch fitted and that is what I have ... I have a three position toggle switch ... 1 = Auto ... Centre = OFF .... 2 = Manual over-ride ON

The type of switch you have is encapsulated reed type and well known for what you have - getting stuck. I have burnt out two of those in the past where they stuck in ON position ...

 

[funinthesun]

something like this would be okay then?

 

[Refueler]

Yes or as I have .. a simple toggle switch with 3 positions.

The float switch is only a break in one wire to the pump .. arm lifts up and the 'break' closes to make contact.

In fact you could just add a simple ON - OFF switch across the float switch wires .. basically bypassing the switch. But a 3 position gives you the extra option of switching off the whole completely ...



Very simple way ...

 

[funinthesun]

That's great, thanks for your help

 

[vas]

Just make sure the switch will withstand the current of the pump,!

 

[Refueler]

Just make sure the switch will withstand the current of the pump,!

Agreed ..... my 3 way is a 10A job.

I would comment though that the float switch he has - if its anything like the ones I had - are the amps limiting factor ... they cannot handle anything but smallest pump.

 

[Catalina36]

Reed switches like that often have only a very small current capacity, sometimes less than 1 amp, nowhere near enough to drive a pump. Your auto electrics supplier has 30 amp 12v relays for under a fiver, handy for standing between the reed switch and the pump.

 

[funinthesun]

It looks like the reed switch has tiny cables leading to another switch that triggers the pump. I’m hoping I can interrupt these tiny cables with the 3 way switch.

 

[Assassin]

They are not a power feed, merely a trigger, usually for a relay which would generally consume 20-30 M/a and they reed would handle that easily, it is a standard reed switch and BMW ones are similar in their cooling systems, and there are many commercial variants of this switch.