Lennox 14A45 Pressure Switch

The Lennox 14A45 Pressure Switch is a high-precision, two-stage OEM furnace replacement designed to ensure safe ignition and optimal inducer airflow. This dual pressure switch is factory-calibrated with specific set points of .50" and .90" WC, acting as a critical safety limit that confirms the draft inducer is pulling sufficient vacuum before allowing the gas valve to open. As a direct replacement for the legacy Lennox 103613-03 and UniControl 104549-03, this 2-stage pressure switch features an SPST-N.O. configuration and is rated for 5A resistive at 24VAC. The 14A45 pressure switch is engineered with durable stainless steel calibration springs and fine silver contacts to prevent pitting and ensure long-term reliability in high-efficiency heating systems. Designed for a wide range of Lennox and Allied brand furnaces, including EL296 and 95AF series models, it provides the precise pressure monitoring required to prevent startup errors or draft-related lockouts in demanding residential and commercial HVAC applications.

Key Benefits

• Precise Airflow Sensing: Calibrated specifically to .50/.90 PSI (WC) to ensure the draft inducer motor is operating within safe factory parameters.
• OEM Compatibility: Serves as the official direct replacement for part numbers 103613-03 and 104549-03, ensuring perfect fitment and electrical alignment.
• Enhanced HVAC Safety: Prevents furnace ignition under unsafe draft conditions, protecting the heat exchanger from improper combustion.
• Robust Construction: Built with high-grade components to resist the vibration and heat typical of furnace heating compartments.
• Multi-System Support: Compatible with several Lennox, Armstrong, and Ducane high-efficiency furnace models.

Common Questions

How do I know if my 14A45 pressure switch is failing?
Common symptoms include the inducer motor running continuously without ignition or the control board flashing a fault code for an "open pressure switch." You can test continuity with a multimeter while the inducer is running to verify if the switch is closing at the required .50" or .90" WC thresholds.

Is the 14A45 compatible with high-altitude kits?
This switch is calibrated for standard elevations. For installations above 7,500 feet, you may require a specific high-altitude pressure switch kit (e.g., 74W37 or 93W75) as air density affects the vacuum pull of the inducer.

Can I use this to replace a single-stage pressure switch?
No. The Lennox 14A45 is a two-stage pressure switch specifically designed for variable capacity or multi-stage furnaces. Using it in a single-stage system will result in improper wiring and system failure.

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.