Description
The Lennox 25B93 is an OEM two-stage pressure switch engineered for precise draft and combustion airflow verification in compatible Lennox furnace systems. By monitoring negative pressure at two distinct set points — -.95 in. WC and -.55 in. WC — this switch confirms that the inducer motor is generating adequate airflow before allowing the burners to fire, protecting the heat exchanger and ensuring safe, efficient operation.
Key Features
- Two-stage pressure switch with dual set points: -.95 in. WC and -.55 in. WC
- Monitors inducer draft to verify safe combustion airflow before ignition
- OEM Lennox replacement part — direct-fit for compatible Lennox furnace models
- Helps prevent unsafe furnace operation due to blocked flue, failed inducer, or restricted venting
- Durable construction for long-term reliability in demanding heating applications
How It Works
The pressure switch is connected via tubing to the inducer housing or flue collector box. As the inducer motor ramps up, it creates a negative pressure. The switch closes its contacts only when the measured pressure meets or exceeds each stage’s set point, signaling the control board that conditions are safe to proceed with ignition. If pressure drops below the set point at any time during operation, the switch opens and shuts down the burners to prevent hazardous conditions.
Application
- Designed for use in Lennox two-stage gas furnaces
- Replaces worn, failed, or out-of-spec OEM pressure switches
- Ideal for HVAC technicians performing routine maintenance or diagnostic repairs
Why Choose OEM?
Using a genuine Lennox OEM pressure switch ensures proper calibration, fit, and function — maintaining your system’s warranty and delivering the performance and safety standards Lennox equipment is built to achieve.
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