Automatic Control Switches for Big Pumps

Most of the basic pumps are controlled by turning on or off the power supply with the help of a mere switch. Small pumps can be controlled in this way but as the voltages and amperes get higher in case of bigger pumps, e.g. irrigation pumps, a simple switch will not be sufficient & safe to handle. A bigger switch has to be used to handle the load. Most pump control circuits are designed using a relay circuit that keeps the user away from the pump voltage. In case you want to automate the control of the pump, simply replace the manual switch in the circuit with an automatic switch.

Automatic pump switches are of various types and work on different techniques. Here we give brief description on different types of automatic pump switches that are used most commonly with most of the pumps.

Electric Timer: With the help of electric timers you can turn the pump on and off at predetermined times. A low voltage timer can control the starting and stopping of high voltage pumps using a relay. You can even hook the pump up to your computer with the right voltage relay.

Pressure Switch: Pressure switches are often found with well pump. When pressure in the pipes drop below, pressure switch turns on the pump and when the pressure gets to higher level it turns it back off. A typical installation of pressure switch will have a pressure tank that stores pressurized water in order to avoid rapidly on and off cycle due to pressure changes. The pressure tank serves as a reservoir to stabilize the pressure in the system. Pressure switches are adjustable so it is easy to modify the on and off pressure settings within a limited pressure range.

Irrigation Controller: Irrigation controllers have a pump start circuit built into them to control. When the wires of the switch is connected to the controller pump start terminals, and the irrigation controller will turn the pump on whenever it turns on a valve. If pump has a low voltage starter circuit with a relay then another one is required for installation for the irrigation controller.

Flow Switch: Flow switches are used on booster pumps for automatic control. It turns on the pump when the switch detects flow in the pipes. Thus as you open a sprinkler valve, the water starts flowing and the pump is switched on. It works only in the case water is already pressurized and you need to increase the pressure. 

Apart from these switches mentioned above, pumps can be controlled using combination of one or more of these switches. Combining one or more of these switches would provide various ways to turn on and off the pumps. One very common application is one relay operated by the irrigation controller and a second relay controlled by both a pressure switch and a manual override switch.