The upper level float switch is designed for high level shut off for a commercial reverse osmosis system. It is generally used in a atmospheric holding tank for a high level shut off.
The level control is a normally closed switch that opens when the float raises to the 12 O' clock position, which means it is full. When water is drawn from the tank and the float switch reaches the 3 O' clock position or lower, the switch again closes and allows the RO system to turn on and produce water until the switch once again raises to the 12 O clock position and opens the switch which turns off the RO system. Float switch is 115v.