York S1-024-36052-018 SPNO Fall Pressure Switch Close On 0.20" WC

The York S1-024-36052-018 Fall Pressure Switch is a safety part used to monitor an HVAC system for a low-pressure level and sound alert or stop operation to avoid harm. It is an SPNO switch which means it is open normally and will close only when pressure is below a certain pressure. This switch is rated for 0.20” water column, which means the minimum amount of pressure drop is needed to trigger the switch. The switch works based on a diaphragm that is sensitive to pressure variations. When the pressure reduces to the limit, the diaphragm moves and opens the switch to give a signal or perform an action.