Williams P323379 Limit Switch

The Williams P323379 Limit Switch is a critical safety component designed for high-limit temperature monitoring in gas furnaces and heating units. Featuring a 330F CO temperature rating, this manual reset vent limit switch ensures that the combustion system shuts down immediately if internal temperatures exceed safe operating parameters. As an OEM Williams replacement part, it provides precise overheat protection to prevent heat exchanger damage and hazardous conditions. The manual reset functionality is a key safety requirement, ensuring that the HVAC system cannot restart until a technician identifies and resolves the underlying cause of the thermal trip, such as a localized combustion chamber blockage or restricted airflow.

Built for durability in high-heat environments, the P323379 switch features a compact design for easy panel mount installation within the cabinet interior. It operates with a single-pole double-throw (SPDT) action, typically opening on temperature rise to break the circuit. Integrating this genuine Williams Comfort Products limit control maintains the engineered safety standards of the original equipment, ensuring reliable temperature regulation and electrical continuity under standard 115V loads.

• Precise Thermal Cut-out: Calibrated to trip at exactly 330°F to provide a failsafe against thermal overload.
• Manual Reset Safety: Prevents automatic equipment restarts, allowing for professional diagnostic verification after a trip.
• Direct OEM Fit: Guaranteed compatibility with specified Williams furnace models for seamless field replacement.
• Rugged Construction: Engineered to withstand the rigors of industrial and residential cabinet environments.

What causes a manual reset limit switch to trip?
Common triggers include restricted airflow from a dirty filter, a failing blower motor, or cracked heat exchangers causing localized hot spots.

Can I replace an auto-reset switch with this manual reset model?
No. You must always use the specific reset type designated by the manufacturer’s original specifications to maintain the safety listing of the furnace.

How do I test the continuity of the P323379?
Using a multimeter set to ohms, you should see near-zero resistance across the terminals when the switch is cool and reset. An open circuit (infinite resistance) indicates a tripped or failed switch.

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.