Lennox 71J07 Limit Switch

The Lennox 71J07 Limit Switch is a high-precision, normally closed safety component designed for critical temperature regulation in heating systems. Engineered by Therm-O-Disc (Model 36TX11, 36T series), this disc-style limit switch features an automatic reset function that ensures seamless system recovery once temperatures stabilize. With an open temperature threshold of 175°F and a close temperature of 155°F, this L175-20 limit switch effectively monitors the heat exchanger, preventing hazardous overheating by breaking the circuit if the furnace exceeds safe operating parameters.

For service technicians, this 155-175F flame rollout switch replacement is essential for troubleshooting "limit circuit open" 1-flash diagnostic codes on Lennox furnace units. The 71J07 (also indexed as 1J0701) offers a robust 4-inch footprint for secure mounting and OEM furnace part compatibility, ensuring HVAC system protection in residential and industrial air handlers. By maintaining the furnace high limit switch integrity, you protect the heat exchanger from thermal stress and ensure consistent blower motor activation during high-heat events.

• Precise Thermal Safety: Accurately opens at 175°F and closes at 155°F to maintain specific 20-degree differentials.
• Automatic Reset Logic: Eliminates manual intervention after brief over-temperature events, reducing unnecessary service calls.
• Genuine OEM Build: Direct Lennox replacement part ensures exact mounting alignment and terminal compatibility.
• Enhanced System Durability: Prevents excessive thermal cycling that leads to premature heat exchanger failure.

• What causes a Lennox 71J07 to trip frequently? Often linked to restricted airflow from a dirty 5-inch MERV filter, a failing blower motor, or closed supply registers.
• Can I use this switch in non-Lennox systems? While technically a 36TX11 series switch, it is calibrated specifically for Lennox heat exchanger tolerances; cross-referencing the L# rating is critical.
• How do I verify the switch is faulty? Use a multimeter to check for continuity; if the switch is open at room temperature, the internal bimetal disc has failed.

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.