Lennox 42J05 Limit Switch

Maintain precise thermal regulation in your commercial or residential equipment with the Lennox 42J05 Limit Switch. This genuine OEM Lennox 42J05 component is a fixed temperature limit switch designed to protect the system by interrupting the circuit when the temperature reaches the 170°F threshold. Engineered with an auto reset feature (L170-40F), it restores operation once the temperature drops below the differential, typically around 130°F, ensuring continuous protection without manual intervention. This 130-170F AUTO limit switch is a critical safety bypass for various Lennox HVAC systems including GCS16, LGB036H, and GCS20R series units. Its snap-disc construction provides reliable, surface-mounted thermal sensing to prevent heat exchanger damage and hazardous overheating conditions. When replacing high-limit controls, verified Lennox HVAC replacement parts like the 42J05 ensure exact mounting alignment and electrical terminal compatibility for professional service and maintenance calls.

Key Benefits

• Precision Thermal Calibration: Factory-set to open at 170°F and close at 130°F for accurate high-limit protection.
• Integrated Auto-Reset Logic: Eliminates downtime and manual resets by automatically closing the circuit after the heat exchanger cools.
• Broad Model Compatibility: Drop-in replacement for Lennox 42J0501 across GCS16, GCS20, and LGB product lines.
• OEM Safety Reliability: High-grade HVAC high limit switch construction ensures long-term resistance to thermal cycling.

Common Questions

What are the specific temperature settings for the Lennox 42J05?
The 42J05 is an L170-40F switch, meaning it is designed to open at 170°F and has a 40°F differential, typically closing (resetting) at 130°F.

Is this a manual or automatic reset switch?
This is an auto-reset limit switch. It does not require a technician to manually push a button; it will re-engage once the temperature reaches the lower limit.

Can I use this for GCS16 and GCS20 series furnaces?
Yes, this Lennox furnace limit switch is a verified OEM replacement for GCS16-024 through GCS16-270 and GCS20R series units.

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.