The 3L01-190 Snap Disc Limit Switch (White-Rodgers / Copeland Comfort Control) is an automatic reset temperature safety control designed to protect HVAC, heating, and refrigeration equipment from excessive operating temperatures. Featuring a 190°F fixed cut-out temperature and a 40°F differential, this open-on-rise switch interrupts the electrical circuit when temperatures exceed safe limits and automatically resets after cooling, helping protect critical system components from heat-related damage.

Cross-Reference

• 3L01-190
• 3L01190
• L190-40F
• 4601-2358
• 3-3797
• White-Rodgers 3L01-190
• Copeland Comfort Control 3L01-190

Direct OEM

White-Rodgers 3L01-190

Compatible Brands

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

Application

Used in HVAC and refrigeration equipment to:

• Protect equipment from overheating
• Open the safety circuit at 190°F
• Automatically reset after cooling
• Protect compressors, heaters, motors, and control circuits
• Prevent heat-related component failures
• Maintain reliable equipment operation

Related Components

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

Technician Notes

The 3L01-190 is an automatic reset, open-on-rise snap disc limit switch. Under normal operating conditions the contacts remain closed. When the sensing surface reaches 190°F, the contacts open to interrupt the circuit and prevent overheating. Once temperature falls by the switch differential, the contacts automatically reset and restore circuit operation.

This limit switch replaces 4601-2358 and 3-3797 and is commonly used in HVAC, refrigeration, and equipment protection applications where automatic reset functionality is required.

Common Symptoms of Failure

• Equipment shuts down unexpectedly
• High-limit or safety circuit faults
• Intermittent operation
• No continuity through switch contacts
• Repeated temperature-related shutdowns
• System lockout conditions
• Compressor or heater protection trips
• Failure to restart reliably

Installation Tips

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

Recommended Inspection Items

• Blower motor operation
• Airflow restrictions
• Coil cleanliness
• Electrical terminals
• Wiring harness condition
• Compressor operating temperature
• Control board diagnostics
• Supply voltage
• Ventilation around equipment