Most well pumps have a range of 30 to 50 PSI, meaning they turn on at 30 PSI and turn off at 50 PSI. If you have a submersible pump, it will probably be set to 40 - 60. Some smaller jet pumps are set to 20 - 40. These ranges are also sometimes called the “cut-in and cut-out” pressures, meaning the pump will “cut-in” (turn on) at the bottom of the range and “cut-out” (turn off) at the top of the range.
For instance, if your pump is set to 30 - 50, you could use the center nut to raise it to 35 - 55. Or, you could lower it to 25 - 45. Lowering the PSI range will lower the pressure, meaning your water won’t come out as forcefully. Raising the range will raise the pressure, meaning your water will come out more forcefully.
For example, if your pump is set to 30 - 50, you’d use the right nut to change it to 30 - 45. Raising the pressure of your range can damage the pump, especially if you adjust it a lot. You’d only want to do this if your range was already too low (meaning you had less than 20 PSI in your range).
Unfortunately, the pressure switch won’t tell you how much you’re adjusting the PSI until you turn it back on. Do your best to raise or lower the pressure accurately, but be prepared to do some adjusting.
When the pump turns on, that’s your new cut-in pressure. When it turns off, that’s your new cut-off pressure. If you do need to adjust the pressure switch again, be sure to turn the breaker off before doing so.
