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Water Pump Pressure Switch

Water Pump Pressure Switch

The water pump pressure switch turns the pump on and off, on the basis of the cut-off and cut-on pressure. This write-up provides instructions for adjusting this switch.
Smita Pandit
Last Updated: Apr 22, 2018
A water pump pressure switch is designed to turn the pump on when the pressure inside the water system falls below a predetermined setting. This switch contains sensors, therefore, when the pressure goes below the setting, the switch turns the pump off, and when the pressure is above the predetermined setting, the pump is turned on. Sometimes, wrong pressure settings can cause problems that can affect the water flow and pressure. If you are facing this problem, you must check this switch. Sometimes, factory settings might need to be changed. Adjusting the settings might help in correcting the working mechanism of the pump.
Common Problems
The pressure switch controls the working of a well pump. The pump might not work properly, the switch if faulty. At times, the settings might need to be changed. Problems could also arise, if the pressure switch sensing port is blocked by debris in water. The switch consists of a set of pressure adjustment springs and electrical contacts. The set of adjustment springs work together and perform the task of switching the pump on and off. Problems could arise if the pump off range is set very low. As a result, the pump might run continuously and it might get damaged. Wrong settings lead to an erratic well pump and pressure control behavior. If you have ever seen the switch, you might have seen two pairs of electrical contacts. Sometimes, problems could be caused due to corrosion on the electrical contacts. Before you check the electrical contacts, make sure that you turn off the power source. Check for the signs of corrosion. You could either clean the contacts with emery cloth or replace them if need be.
How to Adjust this Switch
In order to change the settings, it would be best to read the manual provided by the manufacturer. You might have to adjust the settings to change the pump cut-on, that is the pressure when the pump is turned on, and the pump cut-off, the water pressure range when the pump gets turned off. The cut-on pressure is usually 20 pounds per square inch (PSI) less than the cut off pressure. To change the settings you need to remove the cover of the switch. Since there are live electrical contacts, you must disconnect the electrical power before taking the switch cover. You will now see a set of adjustment springs. The larger nut in the pump pressure control switch adjusts the pump cut-on and cut-off pressures simultaneously. When you turn the large nut clockwise, both the cut-on and cut-off pressure range is raised. Turning the nut counter-clockwise will decrease the operating range. When you make these adjustments, the gap between the cut-on pressure and the cut-off pressure doesn't change. The nut on top of the smaller spring in the switch is used to narrow or widen the gap between the pump cut-on and cut-off pressures. When you tighten or turn the small nut in a clockwise direction, the cut-off pressure will increase and when you loosen the nut or turn it in the counter-clockwise direction, the cut-off pressure will come down. Always remember not to loosen the nut too much. If the cut off pressure is set at a range that is lower than the cut-on pressure, the pump will keep running and might get damaged. In case, the pump has been completely damaged, you will have to replace it.
The next time you feel that the water system is not functioning properly, make sure that you check the pressure switch. In case, adjusting the switch doesn't help, you might have to replace the switch.