Lennox 25B94 - Lennox 104549-21, 2-Stage Pressure Switch, Set Point High 0.80" W.C.; Set Point Low 0.40" W.C.

 

Lennox 25B94 (104549-21) is a genuine OEM 2-stage pressure switch designed to monitor and verify proper draft and airflow conditions within compatible Lennox gas furnaces. This safety control plays a critical role in furnace operation by ensuring the inducer motor and venting system are functioning correctly before allowing ignition and continued heating cycles.

This dual-stage pressure switch features two precisely calibrated set points, allowing it to accurately respond to different operating stages of the furnace. The high-stage set point is rated at 0.80 inches water column, while the low-stage set point is rated at 0.40 inches water column. These values ensure reliable system performance, proper combustion airflow, and protection against unsafe operating conditions.

Manufactured to Lennox factory specifications, this pressure switch is engineered for exact fit, dependable switching performance, and long-term durability. It is intended for use in specific Lennox two-stage furnace models and should always be matched by part number to ensure compatibility.

As an OEM replacement component, Lennox 25B94 helps restore correct furnace operation, reduce nuisance shutdowns, and maintain system safety and efficiency. Ideal for professional HVAC technicians and qualified service personnel performing repairs or maintenance on Lennox heating equipment.

 

Product specifications

Manufacturer: Lennox
Lennox part number: 25B94
OEM reference number: 104549-21
Type: 2-stage pressure switch
High-stage set point: 0.80 in. W.C.
Low-stage set point: 0.40 in. W.C.
Application: Gas furnace safety and airflow verification
Installation: Direct OEM replacement
Condition: New, factory original part

 

This Lennox pressure switch is recommended for applications where maintaining proper airflow sensing and furnace safety control is critical. Always verify furnace model compatibility prior to installation.