Description
The Lennox 11U70 is an OEM replacement .80″ W.C. pressure switch designed to monitor and verify proper draft pressure in Lennox gas furnaces. Pressure switches are a critical safety component — they confirm that the inducer motor is operating correctly and that adequate negative pressure (draft) is established before allowing the gas valve to open and ignition to occur. If the required pressure is not achieved, the switch remains open, preventing unsafe furnace operation.
Key Features
- OEM Lennox replacement pressure switch (SKU: 11U70)
- .80″ W.C. (inches of water column) setpoint for precise draft sensing
- Designed to confirm proper inducer/draft blower operation before ignition
- Helps prevent unsafe furnace operation due to blocked flue, failed inducer, or improper venting
- Direct OEM replacement for compatible Lennox furnace models
- Reliable switching action for consistent, long-term performance
How It Works
During furnace startup, the inducer motor creates a negative pressure (vacuum) in the heat exchanger and flue system. The pressure switch senses this vacuum and closes its contacts when the correct pressure threshold — in this case .80″ W.C. — is reached. This signals the control board that it is safe to proceed with ignition. If the pressure is insufficient (due to a blocked vent, failed inducer, or cracked heat exchanger), the switch remains open and shuts down the ignition sequence, protecting the system and occupants.
Application
- Compatible with select Lennox gas furnace models requiring a .80″ W.C. pressure switch
- Ideal for HVAC technicians performing routine maintenance, diagnostics, or component replacement
- Always verify compatibility with the specific furnace model before installation
Why Choose OEM Lennox Parts?
Using genuine Lennox OEM replacement components like the 11U70 ensures proper fit, function, and reliability. OEM parts are engineered to the exact specifications of your Lennox equipment, reducing the risk of callbacks and ensuring the system operates as designed.
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