Pressure switch does not shut off pump sometimes:

To make the pump turn on/off automatically, you need to have this combination: pump, transformer, pressure switch (TSO) and solenoid valve (ESO). If you only have a pump, transformer, and pressure switch, the pump will not be able to turn off by itself.
The pressure switch should be connected at the pure water output line, so that when the tank is full, it would shut off the pump. The solenoid valve should be connected in front of the pump, so when the tank is full, it can shut off the water supply.


Quantity of nozzles you have will play a factor as well. You’ll need to adjust the pressure setting on the pressure switch to accommodate your application and the quantity of nozzles. To do so, you’ll need to use a small hex wrench to turn the hex screw clockwise 1 to 2 turns; then turn on your pump and water; allow the pressure to build up. This may take a few minutes.