Lennox 42J07 Limit Switch

As an HVAC technician, you know that a reliable Lennox 42J07 Limit Switch is non-negotiable for system safety and performance. This genuine OEM replacement part is an auto-reset limit switch engineered to monitor internal plenum temperatures in a variety of Lennox residential and commercial units. Specifically designed as an L220-40F limit switch, it features a fixed temperature setting that triggers the circuit at a high limit of 220°F and resets once the system cools by 40°F, returning to a closed state at 180°F. This 180-220F auto limit switch provides critical protection against overheating, preventing damage to the heat exchanger and potential safety hazards. Built with a durable bimetallic disc for precise thermal response, the Lennox 42J07 ensures your furnace, air handler, or package unit maintains proper cycling especially when facing restricted airflow or blower issues. Replacing a worn or drifting switch with this factory-spec component is essential for restoring the HVAC high limit safety standards of the original equipment.

• Precise Thermal Control: Factory-calibrated L220-40F settings (opens at 220°F, resets at 180°F) for accurate system ??.
• System Compatibility: Fits professional-grade Lennox GCS24, GCS24D, and LGB series units, ensuring a seamless drop-in fit.
• Auto-Reset Functionality: Automatically restores the circuit after a high-temperature trip and sufficient cooling period.
• OEM Reliability: Genuine Lennox part designed to withstand the high-cycle demands of professional HVACR environments.

What causes this limit switch to trip frequently?
Frequent tripping is usually a symptom of restricted airflow. Check for a clogged air filter, blocked return vents, or a failing blower motor that isn't moving enough air across the heat exchanger.

Is the 42J07 a manual or automatic reset switch?
This is an automatic reset switch. It does not require a technician to push a button; it will re-engage once the temperature drops below its 180°F reset point.

Can I use a switch with a different temperature rating?
No. In technical applications, you must match the manufacturer's specified temperature range exactly to maintain the safety certification and operational integrity of the unit.

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.