Water well pumps make water work for communities all over the world. However, the pump wouldn’t be able to do its job as efficiently without the pressure switch and pressure tank. While A.Y. McDonald sells each component of the system, customers tend to have a lot of questions about the function of the pressure switch. Allow us to provide a crash course on the what, the where, and the how of a pump’s pressure switch:


What is a pressure switch?

The pressure switch is an electrical switch that makes contact to start the pump when the pressure drops and breaks contact to stop the pump when the pressure reaches the high setting. A low pressure cut out switch in particular will prevent the pump from being damaged if the well cannot keep up with the water demand. The pressure switch’s most common application is for submersible and jet pumps.


Where is the pressure switch located?

Pressure switches are most often mounted on the high pressure side of the pump or at the tank. This is so they can have a fluid connection between the incoming and outgoing water pressure.


What are the parts that make up a pressure switch?
The sensing element of a pump’s pressure switch consists of a flexible diaphragm. Changes are sensed by the flexible diaphragm and transferred to a mechanical lever, which operates the contacts. (Picture shown to the right)


How does the pressure switch operate?

The pressure switch settings determine when the pump’s pressure switch operates. Common switch settings would include 20/40, 30/50, 40/60. The low number is when the pump turns on (cut-on) and the high number turns the pump off (cut-off). The cut-on pressure is typically 20 PSI less than the cut-off pressure. Most homes require a pressure range of 40 PSI to 60 PSI, which means that when the pressure drops to 40 PSI the pump turns on and brings the pressure back to 60 PSI before turning off again.



For a water well, the combination of the pump, pressure switch, and pressure tank allow water to flow through a structure. While each part is essential to the operation of the system as a whole, it’s essential to have a clear understanding of how your pressure switch operates since it determines when the pump is running.

It not only takes a great product in order to stand out in this industry; it also takes great customer service. Since 1856, A.Y. McDonald has been providing the ideal pumping solutions for you and your community – and this includes pressure switches. Call us at 1-800-292-2737 or visit the contact us section of our website in order to have all your pump needs taken care of. To simply learn more about pressure switches and other pump components, feel free to take our Pumps AYU courses.