Lennox 49L91 SPST Pressure Switch 0.51" WC

The Lennox 49L91 pressure switch that is designed to be used in HVAC systems only. It is a small device that is normally measuring the air pressure in the system and is connected using single-pole, single-throw (SPST) switch. This means the switch opens or closes an electrical circuit when the air pressure is at a certain level; normally 0.51 inches of WC. This helps to regulate the air pressure in your HVAC equipment and hence its safe and efficient use by the Lennox . It can perform a range of operations depending on the change in pressure.