Johnson Controls P70AA-118 Fan Cycle Control 100/400 PSI

The Johnson Controls P70AA-118 Fan Cycle Control 100/400 PSI operates through a pressure-sensitive diaphragm that reacts to changes in system pressure to activate a fan circuit. As system pressure rises to the upper setpoint, the internal mechanism actuates electrical contacts to energize the fan circuit and assist in increasing the heat dissipation. When pressure drops to the lower set point, the diaphragm relaxes and the contacts open, turning the fan off to reduce unnecessary operation. It is installed in systems, typically mounted on the high-pressure line or condenser section, where fan cycling based on pressure conditions is required.