Lennox 33W19 Dual Pressure Switch

The Lennox 33W19 is a 2-stage dual pressure switch which is a safety component used in HVAC appliances such as furnaces and air handlers. It checks the pressure in the system and sends electrical signals when the pressure is high or low depending on the standard pressure; in this case, the high pressure is set at 1.37” W.C and the low pressure at 0.30” W.C. Constructed from steel for longevity, this particular switch is designed to run on a standard 24V power supply with a maximum current of 5A. The contact arrangement used is the SPST-N.O. enabling the switch to make a circuit when pressure is applied to the set points.