The 3L01-140 Snap Disc Limit Switch (White-Rodgers / Copeland Comfort Control) is an automatic reset temperature safety control designed to protect HVAC and refrigeration equipment from overheating. Featuring a 140°F fixed cut-out temperature and 100°F fixed cut-in temperature, this open-on-rise switch automatically interrupts the circuit when excessive temperatures occur and restores operation once temperatures return to a safe level.

Cross-Reference

• 3L01-140
• 3L01140
• 60T11 Series
• 60T11 Snap Disc Limit Switch
• White-Rodgers 3L01-140
• Copeland Comfort Control 3L01-140

Direct OEM

White-Rodgers 3L01-140

Compatible Brands

• White-Rodgers
• Emerson
• Copeland
• York
• Coleman
• Luxaire
• Universal HVAC Applications
• Refrigeration Equipment Manufacturers

Application

Used in heating, cooling, and refrigeration systems to:

• Protect equipment from overheating
• Open the control circuit at 140°F
• Automatically reset at 100°F
• Safeguard motors, heaters, and electrical controls
• Provide dependable temperature-based safety protection

Related Components

• Snap Disc Limit Switch
• Fan Switch
• Fan & Limit Control
• High Limit Control
• Control Board
• Transformer
• Compressor Contactor
• Temperature Sensor

Technician Notes

The 3L01-140 is an automatic reset, open-on-rise snap disc limit switch. Under normal conditions, contacts remain closed and open when the sensing surface reaches 140°F. Once temperatures fall to approximately 100°F, the switch automatically resets. Always match temperature ratings, terminal configuration, mounting style, and switch action when replacing.

Repeated trips often indicate restricted airflow, dirty coils, defective fan motors, failing bearings, or excessive equipment operating temperatures.

Common Symptoms of Failure

• Equipment shuts down on temperature safety
• Intermittent operation
• Open safety circuit
• Heating or cooling lockout
• No continuity through switch contacts
• Frequent nuisance trips
• Reduced equipment reliability
• Failure to restart after overheating

Installation Tips

1. Disconnect power before servicing.
2. Verify replacement temperature ratings match the original component.
3. Confirm switch action is "Open on Rise."
4. Mount securely against the original sensing surface.
5. Inspect wiring terminals for corrosion or heat damage.
6. Check airflow and operating temperatures.
7. Test continuity before startup.
8. Verify proper operation through a complete cycle.

Recommended Inspection Items

• Blower motor operation
• Condenser fan operation
• Airflow restrictions
• Coil cleanliness
• Electrical terminals
• Wiring harness condition
• Temperature rise across equipment
• Control board diagnostics
• Supply voltage