Lennox 25B93 – Lennox 104549-20, 2-Stage Pressure Switch, Set Point High 0.95" W.C.; Set Point Low 0.50" W.C.

 

This Lennox 25B93 (Lennox 104549-20) 2-Stage Pressure Switch is a critical safety and performance component used across a wide range of Lennox high-efficiency gas furnaces. Designed to provide accurate airflow verification, this pressure switch ensures the furnace operates within proper draft and combustion parameters by monitoring pressure levels in multi-stage heating systems. With precise set points at 0.95" W.C. (high stage) and 0.50" W.C. (low stage), it delivers stable and reliable operation in demanding HVAC environments.

Engineered for compatibility with select Lennox Signature, Elite, and Merit Series furnaces, the 25B93 pressure switch offers dependable performance, long service life, and consistent furnace cycling. It is commonly replaced when a system experiences ignition issues, error codes related to airflow or pressure faults, or inconsistent stage operation.

This factory-authorized Lennox component ensures seamless replacement, proper fitment, and OEM-level reliability that meets Lennox’s exact performance specifications.

 

Technical Specifications

• Part Number: Lennox 25B93
• Catalog/Manufacturer Number: 104549-20
• Type: 2-Stage Pressure Switch
• High Stage Set Point: 0.95" W.C.
• Low Stage Set Point: 0.50" W.C.
• Application: Draft/combustion airflow verification in multi-stage gas furnaces
• Electrical Rating: Low-voltage HVAC control circuit
• Furnace Compatibility: Select Lennox high-efficiency models (varies by unit; verify with model and serial number)
• OEM Replacement: Yes – factory-authorized Lennox part