There may be some confusion when it comes to adjusting a pressure switch on a water pump, even though it is a simple process; most pressure switches include an adjustment bolt at one end of the housing.
Once you find the central bolt, you will need to screw downward to compress (or upward to decompress) the spring. This will change the pump’s pressure range to start – or pause – its work. It is as easy as that! Of course, the difficult part is securing a proper pressure range in your water pump system — more on this below.
What Does a Pressure Switch Do on a Water Pump?
A pressure switch is a part of your water pump boosting system that regulates the water flow pressure. Essentially, you switch on and off the pump to get a stable water flow.
Pressure switches work by measuring the water pressure in a pipe. When there is insufficient water pressure, the pressure switch automatically turns on the pump to reach the desired pressure, and it stops once the pressure reaches the maximum desired level.
What are the Cut-in and Cut-out Points of a Pressure Switch?
All water pump boosting system pressure switches have two operating points, known as the cut-in and cut-out settings. The cut-in point indicates the falling pressure, while the cut-out point indicates the rising pressure. To make it simple, one point means the pressure on the system is too low, and the other indicates when the pressure reaches the maximum desired level.
Every pressure switch works within a range based on the cut-in and cut-out points. This range is known as a “differential,” and it can be adjusted based on the desired pressures. For example, if the cut-in is 40 PSI, and the cut-out is 60 PSI, the differential is 20 PSI. Typically, most pump boosting pressure switches operate at 20 PSI differential.
Standard Differential Ranges for Different Water Pump Types
Below is a list of the standard differential cut-in and cut-out ranges for different water pump types:
- Submersible pumps typically work between 40 to 60 PSI.
- Centrifugal pumps and jet pumps that are used for typical water pumping applications stay between 20 to 40 PSI or 30 to 50 PSI.
What Should I Know Before Operating a Pressure Switch?
Below are some things you should know before operating a pressure switch on a water pump or pressure boosting system:
- Always make sure to shut down or remove the power source before making any changes to the switch.
- Look for the manufacturer’s factory preset setting. These details are typically inside the pump’s cover or in the product manual.
- Understand the manufacturer’s preset range. For example, a cut-on 30 PSI and cut-off 50 PSI means that the system will switch on every time the pressure drops below 30 PSI, and it will shut down once the pressure reaches 50 PSI.
- Identify the central nut where you will change your pressure settings.
- Take note of the distance between the cut-in and cut-off points. That way, you will have something to reference.
Rules of Thumb When Adjusting a Pressure Switch on a Water Pump
By turning the central nut clockwise, you will increase the cut-on and cut-off range. That means that your system will work at a higher pressure. At the same time, if you turn the central nut counterclockwise, you will decrease the pressure for the system to work.
When you do a complete turn of the nut, you will move the pressure range approximately 2-3 PSI; of course, that exact number varies among products and brands, but it can be used as a fair estimate. Some models use a differential nut that only affects the high-end pressure. For example, rotating the differential nut in a 30-50 PSI configuration will only affect the 50 PSI pressure.
You usually do not adjust the differential unless you have a reason to increase the pressure.
What Are the Most Common Reasons to Adjust a Pressure Switch?
Below are some of the most common reasons to adjust the pressure switch on your water pump or pressure boosting system:
- In Your House Water Pump: The pressure at which the water arrives at your home is not enough, so when you open a faucet or shower in your home’s second story, you do not get the water pressure that you expect.
- For Irrigation Purposes: Your pump cannot lift your sprinkler’s heads for lack of pressure, so you cannot maintain your lawn.
Common Issues to Monitor When Adjust a Pressure Switch
Here are some of the common issues to look out for when adjusting or troubleshooting your water pump’s pressure switch:
- A faulty valve (i.e., a valve that is not able to completely block the water flow)
- Too much water is flowing into the system.
- Sediment or debris in the mainline that connects your switch to the main water line
- Spring losing its capacity to go back to the original position (common with old devices)
- Drastic temperature changes that can interfere with the system’s functioning
For more information, check out our video on How to Adjust a Pressure Switch on a Water Pump.
Caution! If you have not used electricity before, it can be very dangerous. When testing or adjusting electrical parts, use caution, and always turn off the power supply breakers if you are working with electricity. If you are unsure or have doubts, it is always better to wait for an experienced technician who knows the ins and outs of electrical systems before attempting it yourself.