Lennox 14A43 Pressure Switch

The Lennox 14A43 Pressure Switch is a genuine OEM dual-stage pressure switch engineered for high-efficiency Lennox, Armstrong Air, and Ducane furnace models. This 2-stage assembly features factory-calibrated set points of 0.90" W.C. (High) and 0.45" W.C. (Low), providing precise differential pressure monitoring to ensure the inducer motor is creating the correct draft for safe combustion. As a direct replacement for Lennox 103271-01, 104549-01, and 93W77, this HVAC safety switch prevents ignition if it detects a blocked vent, failed inducer, or restricted heat exchanger. Designed for 24VAC systems with a 5 Amp resistive rating, it utilizes SPST-N.O. contacts to maintain a reliable safety loop. Whether you are addressing a furnace pressure switch open error code or performing a modular replacement on a 95AF2 or EL296 series unit, this OEM part ensures exact electrical and 0.57 lbs pneumatic compatibility without the need for field adjustments.

Key Benefits for HVAC Professionals

• Direct OEM Compatibility: Replaces multiple legacy part numbers including 103271-01, 103613-01, 104549-01, and 93W77, ensuring a drop-in fit for Lennox and Allied Air equipment.
• Precise Dual-Stage Calibration: Pre-set at 0.90" and 0.45" water column to match OEM airflow specifications for two-stage heating cycles.
• Critical Safety Protection: Monitors inducer draft and flue pressure to prevent hazardous operating conditions and system short-cycling.
• Rugged Build Quality: Constructed with high-grade diaphragms to withstand the thermal stress and condensation cycles typical of high-efficiency furnaces.
• Simplified Diagnostics: Standard 1/4" spade terminals and barbed hose ports allow for quick multimeter testing and pneumatic verification during service calls.

Common Questions About the Lennox 14A43

What was the previous part number for this switch?
The 14A43 is the current official replacement for the older 103271-01 and 104549-01 models often found in older 2-stage furnaces.

Why is my blower running but the burners won't ignite?
If the control board displays a pressure switch error, the 14A43 may be failing to close due to a blocked flue, a clogged pressure port, or a ruptured internal diaphragm. Always check for water in the tubing on 90%+ furnaces first.

Can I use this on other brands besides Lennox?
While designed by Lennox, this part is the factory-standard for many brands under the Allied Air umbrella, such as Armstrong Air, Ducane, and Concord, provided the W.C. ratings match.

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.