Lennox 71G15 Vent Switch

Professional-grade Lennox 71G15 components are essential for maintaining the operational safety of residential and commercial furnaces. This 120V blocked vent switch is a specialized thermal safety control engineered to monitor flue gas temperatures and detect dangerous obstructions in the vent system. Calibrated to actuate at 280F, this manual reset rollout switch effectively cuts power to the gas valve or ignition control if exhaust gases back up due to a blocked vent pipe or heat exchanger failure. For technicians performing a Lennox furnace repair, the 71G15 serves as a direct OEM replacement part, ensuring the system remains within factory safety tolerances. The yellow dot identifier on the closed-face sensor indicates its specific temperature rating, preventing a limit switch lockout during standard firing cycles. This HVAC safety switch utilizes a SPST (Single Pole Single Throw) configuration to interrupt the 120V circuit, providing a reliable failsafe against carbon monoxide backup and equipment overheating.

• Precise 280-Degree Calibration: Ensures the system shuts down immediately upon detecting a thermal spike caused by restricted airflow.
• OEM Compatibility: Designed specifically for Lennox HVAC equipment, maintaining the integrity of the original safety string.
• Manual Reset Functionality: Prevents the furnace from automatically restarting after a safety trip, requiring a technician to identify and clear the vent obstruction.
• Durable Construction: Built with heavy-duty materials to withstand the high-temperature environment of the burner compartment.

Is the 71G15 a manual or automatic reset switch?
This is a manual reset switch. Once it trips at 280F, a technician must physically depress the reset button after addressing the cause of the high temperature.

What does it mean if my Lennox furnace is showing a blocked vent error?
A tripped vent switch often indicates a physical blockage in the chimney, a failed inducer motor, or a cracked heat exchanger causing rollout.

Can I substitute this with a higher temperature limit switch?
No. Safety switches must match the manufacturer's specified temperature rating (280F for this model) to ensure the system reacts correctly to flue gas backup.

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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.