Lennox Pressure Switch WC SPST Normally Open

The Lennox pressure switch (also called a furnace draft pressure switch or air pressure switch) is an OEM replacement control for Lennox HVAC equipment. It is a single-pole, single-throw (SPST), normally open switch with a set point rated in inches of water column (WC). It senses pressure in the furnace venting system and tells the control board whether airflow is adequate.

Key Features:

• SPST, normally open design: The contacts stay open at rest. They close when the inducer draws enough vacuum, which signals the control that venting is working.
• Safety function: If the vent is blocked or airflow is restricted, the switch stays open. This helps keep the furnace from igniting under unsafe conditions.
• Set point in inches of water column: Each model actuates at a specific WC value, so the switch matches the requirements of the equipment it was designed for.
• Genuine Lennox OEM part: It is built to the manufacturer's specifications for direct replacement.
• Simple service item: It connects with standard tubing and electrical terminals. A multimeter continuity check can help diagnose a faulty switch.

Replacing a worn or failed pressure switch can help fix problems such as the furnace not heating, burners that will not stay lit, or short cycling. Choose the variant whose set point matches your equipment.