Lennox 71K11 Pressure Switch

The Lennox 71K11 Pressure Switch is a critical safety component designed for precise vent pressure monitoring in GHR26 series gas furnaces and compatible commercial HVAC units. This single-pole, single-throw (SPST) switch is factory-set to actuate at 0.75" WC (water column) and features an automatic reset function with a reset threshold of approximately 0.90" WC. Engineered for durability in high-demand environments, the 71K11 ensures the inducer motor has established correct airflow before allowing the ignition sequence to proceed, preventing unsafe operating conditions.

This OEM Lennox replacement part, also identified as part number LB-90973A, comes equipped with dual 1/4" barb connections for seamless integration into existing pneumatic tubing layouts. Technically, the Lennox 71K11 is identical to the 71K1101, offering full interchangeability for contractors performing HVAC troubleshooting or routine maintenance. The electrical contact is rated for 24 VAC at 5 Amps resistive (or 28 VA pilot duty), housing a normally open (N.O.) contact configuration that closes only when the specific pressure differential is achieved. Using a genuine Lennox furnace pressure switch like the 71K11 ensures the unit maintains its original engineering specifications and operational efficiency.

• Direct OEM Compatibility: Verified replacement for LB-90973A, 67K27, and 14K96, ensuring a drop-in fit for Lennox GHR26 units.
• Precise Calibration: Factory-calibrated to 0.75" WC to maintain strict combustion safety and manufacturer airflow requirements.
• Dual Barb Interface: Standard 1/4" barb ports facilitate rapid connection to sensing lines without the need for additional adapters.
• Rugged Construction: Built to withstand the thermal cycling and vibration typical of industrial HVAC and residential furnace cabinets.

Is the Lennox 71K11 interchangeable with the 71K1101?
Yes, the 71K11 is the identical technical match for the 71K1101. Lennox often uses these suffixes to denote packaging variations or revision cycles, but the mechanical and electrical specifications remain consistent.

What are the symptoms of a failing pressure switch in a Lennox furnace?
A faulty 0.75" WC pressure switch typically triggers a diagnostic flash code on the integrated control board, often preventing the igniter from glowing or the gas valve from opening if the inducer draft is not correctly sensed.

Can this switch be used in positive or negative pressure applications?
While commonly used in negative pressure (draft) sensing for furnaces, this SPST pressure switch is designed to actuate based on the pressure differential across its dual barb ports, making it versatile for various HVACR control configurations.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.