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How To Adjust a Pressure Switch

The starting and stopping of a well water pump is typically controlled by a pressure switch similar to the one shown below. The switch is preset with both the cut-on and cut-off pressure. The cut-on pressure is the low pressure that starts the pump and the cut-off pressure is the high pressure that turns off the pump. You may be looking to increase pressure for one of the following reasons: the preset range does not provide satisfactory pressure when the water reaches your home, your shower/faucets are lacking sufficient pressure, or your sprinkler heads require a higher pressure. Adjusting the range can be done by following a few simple steps.

Caution! Electricity can be very dangerous, especially if you are inexperienced. Always use caution working with electricity and turn off power supply breakers when testing components or making any adjustments within the electrical system. If you are not 100% confident you can perform any of these tests safely, call a professional.

Remove the cover on your pressure switch. Factory presets can be found inside the cover of the pressure switch (as shown on right above). To increase or lower both cut-on and cut-off pressure you will turn the nut on top of the large center spring as seen in the picture below. You will turn the nut counterclockwise to lower both cut-on and cut-off pressure or turn the nut clockwise to raise both cut-on and cut-off pressure.

If you adjust your cut-on pressure you will also need to adjust the pressure tank air charge. The pressure tank should be set at 2 PSI less than the cut-on pressure. Click here to see a video: How to Check and Adjust Pressure Tanks or click here to read a blog: How to Check and Adjust Your Pressure Tank

There are very few applications where you should adjust the differential. Adjusting the differential will only adjust the cut-off pressure. Turn the differential nut counterclockwise to lower cut-off pressure or turn the nut clockwise to raise cut-off pressure.

Click on the hyperlinks below to see pressure switch videos on the RC Worst YouTube channel:

Square D Pressure Switch

Low Water Pressure Cutout Switch | Square D M4 Pressure Switch W/ Low Pressure Cut-Off

If you have further questions about your pressure switch or your water system please do not hesitate to call our experts at 855.329.4519.