View Full Version : Connecting two flow switches?

03/08/2002, 07:47 AM

If you have the chance, please give me some pointers in wiring up two float switches...

I have two of the Grainger switches you had listed in your article. I'm using one right now (for about 1 year now) in the sump to turn a small topoff pump on/off. The wires from the switch are basically connected to a plug (to wall for 120v) and outlet. A pump in turn connects to the outlet. When the switch is in its lower position, it completes the circuit and the pump turns on.

To be double as safe, I want to use the second switch, wire the switches together (somehow). If the first switch fails and fills too much water into the sump, the second switch will cut the connection and thus turning off the topoff pump. Is this type of wiring possible?

Thanks in advance.

03/08/2002, 07:05 PM
Yes it is possible. I have a setup just like this for my top off except the second switch is in my RO/DI bucket of top off water. If the bucket gets to low on water it won't let the powerhead run even of the top off switch is calling for it.

All you need to do is disconnect one of your float switch wires and connect it to one of the second float switch wires. Thake the other wire from the second float switch and put it where you disconnected the first float switch wire from. This puts the two float switches in series. Set both float switchs to NC. If the water falls below the lower switch the pump will come on until that switch opens. If it is stuck shut the pump will stop when the water gets to the top switch. HTH