Dual Float Switch Wiring Diagram: A Complete Guide

Float switches are used in many industrial applications to control liquid levels. Dual float switches are an advanced version of regular float switches that ensure more safety and accuracy. In this article, we will discuss what a dual float switch is, how it works, and how to wire it properly.

What is a Dual Float Switch?

A dual float switch is a safety device that is designed to monitor liquid levels in a tank or a pump. It consists of two float switches that are placed at different levels in the liquid container. The first float switch is used to turn the pump on when the liquid level is low, and the second float switch is used to turn the pump off when the liquid level is high.

A dual float switch is used in applications such as sump pumps, sewage pumps, and water tanks where accurate and reliable liquid level control is required. It prevents overflow, dry running, and other potential hazards that could damage the pump or the system.

How Does a Dual Float Switch Work?

A dual float switch works based on the principle of buoyancy. When the liquid level rises, the float switches rise with it, and when the liquid level drops, the float switches fall. The first float switch is placed at a lower level and is used to turn the pump on when the liquid level drops below a certain point.

The second float switch is placed at a higher level and is used to turn the pump off when the liquid level rises above a certain point. The distance between the two floats determines the amount of liquid that can be safely stored in the container or pumped out by the system.

Parts of a Dual Float Switch

A dual float switch consists of the following parts:

  • The first float switch
  • The second float switch
  • A control panel or a pump controller
  • Wiring and connectors

Dual Float Switch Wiring Diagram

Wiring a dual float switch is not complicated, but it requires accuracy and attention to detail. You need to follow the wiring diagram carefully and make sure that all the connections are secure and properly insulated.

The following table shows the color codes and functions of the wires in a typical dual float switch:

Wire Color Function
Black Hot wire (120V AC)
White Neutral wire (120V AC)
Green Ground wire (120V AC)
Red First float switch (low level)
Yellow Second float switch (high level)

The following is a step-by-step guide on how to wire a dual float switch:

Step 1: Turn off the Power

Before you start wiring, make sure that the power supply to the pump or the control panel is turned off. This is important for your safety and to avoid damaging the system.

Step 2: Install the Float Switches

Install the first float switch at a lower level in the container, and the second float switch at a higher level. Make sure that the switches are securely fastened and not obstructed by any objects or debris.

Step 3: Connect the Wires to the Control Panel

Connect the black, white, and green wires to the control panel or the pump controller according to the wiring diagram provided by the manufacturer.

Step 4: Connect the Float Switch Wires

Connect the red wire to the first float switch and the yellow wire to the second float switch. Make sure that the wires are properly stripped and connected to the terminals of the float switches.

Step 5: Inspect the Wiring

Inspect the wiring carefully and make sure that there are no loose connections or exposed wires. Also, make sure that the wiring is properly insulated and protected from damage.

Step 6: Turn on the Power

Turn on the power supply and test the dual float switch by filling up the container to different levels. The pump should turn on when the liquid level is low and turn off when the liquid level is high.

Dual Float Switch Wiring Diagram FAQ

1. Can I use a dual float switch with a 220V AC power supply?

Yes, you can use a dual float switch with a 220V AC power supply. However, you need to make sure that the float switch is rated for this voltage, and the wiring diagram is compatible with the power supply.

2. Can I install the first float switch at a higher level than the second float switch?

No, you should not install the first float switch at a higher level than the second float switch. This will result in the pump turning off before the liquid level reaches the desired level, which can cause damage to the system.

3. Can I wire a dual float switch in series with other switches?

Yes, you can wire a dual float switch in series with other switches, such as pressure switches or flow switches. This will provide additional safety and control for the system.

4. What is the maximum distance between the two floats in a dual float switch?

The maximum distance between the two floats in a dual float switch depends on the size and capacity of the container, the flow rate of the pump, and other factors. You should consult the manufacturer’s specifications or a qualified technician for the optimal distance.

5. What is the difference between a normally open and a normally closed dual float switch?

A normally open dual float switch is designed to turn on the pump when the liquid level is low, and turn it off when the liquid level is high. A normally closed dual float switch works the opposite way, turning off the pump when the liquid level is low, and turning it on when the liquid level is high. The choice between these two types depends on the application and the system requirements.

Conclusion

Dual float switches are essential components in many industrial applications that require accurate and reliable liquid level control. Wiring a dual float switch requires attention to detail and accuracy to ensure proper functioning and safety. By following the wiring diagram and the instructions provided in this article, you can wire a dual float switch like a professional.