This is a water pump pressure control switch for perfect pressure control The pressure of the water pump can be adjusted by this switch, you can adjust the pressure according to your needs. It is made of high quality materials, strong and durable. It is easy to install and can be used for a long time. Suitable for most pumps, such as self-priming, jet, garden pumps, etc. Adjustment operation: The pressure switch has been adjusted when leaving the factory, if it is not necessary, try not to adjust it manually. To adjust, follow these steps: (cut off the power first) Remove the plastic cover of the rotary switch. Use a flat-blade screwdriver to adjust the screw on the top of the pressure switch and increase the pressure to the "+" sign Adjust the direction, adjust the pressure in the direction of "-", if the installation is not in harmony I don't know whether to increase or decrease the pressure: 1: Connect the power supply, open the faucet at the water outlet of the water pump, the water pump does not start or the motor does not rotate, adjust the Large switching pressure, adjust to the "+" sign (fine adjustment, semicircle semicircle adjustment), adjust the appropriate pressure position together, the water pump can start working. 2: Connect the power supply, close the faucet at the water outlet of the water pump, the water pump does not stop or starts frequently, lower it Change the pressure, adjust to the "-" sign (fine adjustment, half-circle half-circle adjustment), adjust to the appropriate pressure position, The pump may stop working. Note: When adjusting the pressure switch, make sure that the power supply to the pump is disconnected. To avoid the risk of electric shock!