Lennox 36W91 Limit Control

The Lennox 36W91 Limit Control is a critical safety component designed for high-temperature monitoring within various Lennox furnace and air handler configurations. This L/S switch features a fixed temperature setting with an open temperature of 220°F and a close temperature of 190°F. Engineered for precision, the thermal limit switch functions as a normally closed contact that interrupts the burner circuit if heat exchanger temperatures exceed safe operating limits, preventing equipment damage and ensuring system safety. Contractors frequently specify the 36W91 as a direct replacement part to maintain OEM performance standards. Its robust construction ensures reliable cycling and high-limit protection in demanding residential and light commercial HVAC applications. When troubleshooting furnace lockout codes related to primary limit circuits, verify the L220-30 temperature rating to confirm this component matches your specific heating sequence requirements.

• OEM Compatibility: Direct replacement for Lennox 36W91 and 604313-01, ensuring proper fit and electrical interface.
• Precise Thermal Response: Calibrated 220-degree open and 190-degree close differentials minimize nuisance tripping while providing reliable high-heat protection.
• Durable Construction: Built to withstand high-cycle environments common in forced-air furnaces.
• Standard Connectivity: Utilizes standard spade terminals for rapid tool-less electrical connection during field service.

What causes a Lennox 36W91 limit control to trip?
Tripping is typically caused by restricted airflow, such as a clogged filter, blocked return air, or a failing blower motor, which causes the heat exchanger to exceed the 220°F threshold.

Is the 36W91 a manual or automatic reset limit?
The 36W91 is an automatic reset limit switch; it will re-close the circuit once the sensed temperature drops below the 190°F reset point.

Can I use this limit control in other furnace brands?
While this is a Lennox OEM part, it can be used in other systems if the mounting flak, insertion depth, and L220-30 thermal specifications match the original equipment manufacturer's requirements.

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.