Lennox 20J83 Limit Switch

The Lennox 20J83 Limit Switch (Model 20J8301) is an essential HVAC OEM replacement part engineered for precise thermal management in high-efficiency furnaces. This single-pole, single-throw (SPST) automatic control is factory-calibrated to actuate at 165°F, effectively breaking the circuit to prevent heat exchanger damage or unsafe operating conditions. Once the plenum temperature cools to 135°F, the switch automatically resets, restoring normal system sequence. Identified by the Lennox Red Dot, this component ensures strict compatibility with residential heating units requiring a 135-165F auto limit switch. As a direct-fit Lennox furnace limit control, it eliminates the calibration drift often found in universal aftermarket alternatives, maintaining the original safety parameters of the equipment. Whether you are troubleshooting a furnace short cycling issue or performing a preventive overhaul, this genuine Lennox 20J8301 provides the reliability required for professional service standards.

Key Benefits for Contractors

• Precise Thermal Calibration: Fixed 165°F trip and 135°F reset points ensure the Lennox HVAC system operates within OEM design specifications.
• Genuine OEM Reliability: Using the Lennox 20J83 maintains the UL listing and safety integrity of the furnace cabinet.
• Technician-Friendly Identification: Features the Red Dot indicator for rapid visual verification during field diagnostics.
• SPST Snap-Action Design: Provides clean electrical switching, reducing arcing and extending the life of the control circuit.

Common Technical Questions

Is the Lennox 20J83 interchangeable with the 20J8301?
Yes, the 20J83 and 20J8301 are identical parts. The additional digits are often used in Lennox’s internal inventory systems, but the technical specifications and fitment remain the same.

What causes a limit switch like this to trip frequently?
Repeated actuation of the 165 degree limit switch usually indicates restricted airflow. Check for a clogged 5-inch media filter, a dirty evaporator coil, or an undersized duct system before replacing the control.

Can I use a manual reset switch in place of this automatic model?
No. This is an automatic reset limit control. Replacing it with a manual reset or a different temperature range can lead to system malfunction or safety hazards. Always match the OEM Lennox 20J83 specs.

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.