|| SENSORS < Pressure Switches LOW PRESSURE SWITCH HIGH PRESSURE SWITCH Pressure switches used to control the operation of a filtering system or pump. The high pressure switch is set to turn off at 40psi, and on at 20psi. Used in conjunction with a pressure tank in a reverse osmosis system. The low pressure switch is used to prevent the pressure boost pump from operating when the source pressure is insufficient. The low pressure switch is set to turn off when pressure is below 5psi, and on when pressure exceeds 5psi.