Lennox Two-Stage Pressure Switch

The Lennox Two-Stage Pressure Switch (also called a two-stage furnace pressure switch or 2-stage draft pressure switch) is an OEM replacement safety component for Lennox two-stage gas furnaces. It confirms that the draft inducer motor has created enough negative pressure before the furnace is allowed to light, and it keeps confirming this while the furnace runs.

Key Features:

• Two-stage sensing: monitors pressure at both low-fire and high-fire operation.
• Safety protection: keeps the burners from firing if the inducer does not establish adequate draft. This helps guard against backdrafting and incomplete combustion from blocked venting or a failed inducer.
• Reliable switching: a diaphragm-actuated design opens and closes electrical contacts at calibrated pressure set points. It sends the signal to the furnace control board.
• OEM replacement: a direct-fit Lennox replacement for failed or worn pressure switches during routine service or troubleshooting.

The switch connects to the inducer housing or flue collector box by tubing. If pressure falls below the set point during operation, the contacts open and the burners shut down. Choose the child item whose Lennox part number and pressure set points match your furnace's original switch.