2 x float switches turning pump on and off

Thread Starter


Joined Jun 29, 2011
Hi all,

I have a tank with 2 x float switches in this type


One is at the bottom level and one is at the top level. It is a 230V pump connected to a 12V DPDT relay. I have it wired at the moment so that when the bottom switch is activated it then triggers a timed relay for 30 minutes, the pump turns on, reaches the top level then turns the whole circuit off...

I want to make it so that when the bottom switch is activated it keeps running indefinitely until it hits the top switch..the reason for this is because if the main tanks water level is low it wont be able to pump until I fill it up again (its using an SMS controller so cant see the levels) if I have it the way it is it will turn off after 30 minutes and it wont trigger again.

I have a spare 12V DPDT relay so im hoping I can take the timed one out and use this...the trouble is when the bottom switch activates and triggers the pump once the float raises again it will turn off..

Here is the timed relay...maybe I can modify this so it bypasses the timed side and stays on permanantly until the top switch turns the whole lot off (interupts the 12V supply)

http://www.interfacesolutions.uk.com/ on the products page its called the IS60T 0-60 sec/min timed relay (there isnt a direct link)

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