White-Rodgers 3L01-120 Limit Switch

The White-Rodgers 3L01-120 is a heavy-duty, 3/4-inch snap disc limit switch designed for critical high-limit safety oversight in furnace temperature control and HVAC applications. This SPST (Single Pole Single Throw) control utilizes an open on rise switch action, effectively breaking the electrical circuit when ambient temperatures hit the 120°F fixed cut-out set point. Engineered for professional-grade reliability, this automatic reset limit switch (Therm-O-Disc style 60T11-610000) features a 110°F cut-in temperature, ensuring the system resumes operation once safe thermal levels are restored. The flanged airstream mount and loose ring stainless steel brackets provide a secure, universal fit for standard replacement scenarios. With a robust electrical rating of 10 Amps at 120VAC, this HVAC high limit switch is the standard for technicians requiring precise thermal protection and long-term contact life in residential and light commercial heating equipment.

• Precise Thermal Safety: Fixed 120°F cut-out prevents equipment overheating by immediately opening the circuit upon temperature spikes.
• Automatic Reset Logic: Features a fixed 110°F cut-in, allowing for seamless system reactivation without manual intervention.
• Durable Construction: Built with an aluminum disc cup and stainless steel mounting brackets for superior heat transfer and corrosion resistance.
• Universal Compatibility: The 3/4" flanged airstream mount and loose ring design match standard industry footprints for quick field replacement.
• High Electrical Capacity: Rated for up to 25 Amps resistive at 240VAC, accommodating a wide range of blower and heating motor loads.

What is the difference between "open on rise" and "close on rise" for this switch?
The 3L01-120 is an open on rise limit, meaning the electrical contacts disconnect when the temperature reaches 120°F to shut down the burner or heating element. A close on rise switch is typically used for fan control to start a blower when the plenum heats up.

Can the 3L01-120 be used to replace a manual reset limit?
No, this model is an automatic reset switch. If your system safety circuit requires a manual reset for code compliance or specific diagnostic monitoring, you must use the manufacturer-specified manual reset equivalent.

Where is this limit switch typically mounted?
It is usually installed in the furnace plenum or airstream where it can accurately monitor the internal cabinet temperature to protect the heat exchanger from cracks or fatigue.

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.