I have 2 tanks , one is under another and hopes to pump from under tank to upper one using a 0.5 Hp single phase motor.By connecting float switches for both tank,can I control the motor to turn on when the water level of lower tank is high and switches off when the water level of upper tank is high ( Upper tank has lower capacity than Lower ) and vise versa

  • \$\begingroup\$ Certainly, yes. \$\endgroup\$
    – Transistor
    May 4, 2020 at 22:19
  • \$\begingroup\$ I have question with the circuit, each float switch has 3 wires, what are the wires i need to use \$\endgroup\$ May 4, 2020 at 22:24
  • \$\begingroup\$ You need to edit your question to add links to the datasheet for the switches. We can't guess. \$\endgroup\$
    – Transistor
    May 4, 2020 at 22:27
  • \$\begingroup\$ wiltec.de/float-switch-pump-level-controller-cable-5m.html \$\endgroup\$ May 4, 2020 at 22:32
  • 2
    \$\begingroup\$ I suspect that you want to control one motor with two switches, rather than have the motor control the switches, as the title says. \$\endgroup\$ May 4, 2020 at 22:58

2 Answers 2


According to the datasheet the sensor and under the assumption that it works like https://www.youtube.com/watch?v=tA76sm_jJTk it can be used directly without the need of any additional circuit:

enter image description here

The parts are taken from the datasheet chart 2 and 5.


Yes, by using a relay, wired up as a latch. You have the high-limit switch as SPDT type which can serve as a cut-off.

Here's how it works:

  • The lower tank-high switch energizes the coil.
  • Relay self-energizes through one set of contacts, which latches it.
  • The upper tank-high switch turns off the relay, latch opens.

The connection looks like this:


simulate this circuit – Schematic created using CircuitLab


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