How To Adjust a Pressure Switch

May 18, 2018 By: Shopify API

The starting and stopping of a well water pump is typically controlled by a pressure switch. 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 because the preset range does not provide satisfactory pressure, your shower or faucets are lacking sufficient pressure, or your sprinkler heads require 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.

How to Adjust Cut-On and Cut-Off Pressure

Remove the cover on your pressure switch. Factory presets can be found inside the cover. To increase or lower both cut-on and cut-off pressure, turn the nut on top of the large center spring:

Turn counterclockwise to lower both cut-on and cut-off pressure
Turn clockwise to raise both cut-on and cut-off pressure

Important: 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. See: How to Check and Adjust Your Pressure Tank

How to Adjust the Differential (Cut-Off Only)

There are very few applications where you should adjust the differential. Adjusting the differential will only adjust the cut-off pressure:

Turn counterclockwise to lower cut-off pressure
Turn clockwise to raise cut-off pressure

Shop Replacement Pressure Switches

If your pressure switch is worn, damaged, or simply needs replacing, we carry the full Square D lineup:

Square D G2 30/50 PSI Pressure Switch (Preset) — standard for most residential systems
Square D G2 40/60 PSI Pressure Switch (Preset) — ideal for two-story homes or higher demand
Square D G2+ 40/60 PSI Pressure Switch — upgraded durability
Square D M4 30/50 PSI with Low Pressure Cut-Off — protects pump from running dry
Square D M1 30/50 PSI with Manual Cut-Out Lever — easy manual shutoff for service

Shop Pressure Tanks

Remember: when you adjust your cut-on pressure, your tank air charge must be adjusted too. If your tank is old or waterlogged, it may be time to replace it: