3L09-17 Copeland Comfort Control (White Rodgers) Board Mount Limit Control 250F
3L09-17 Copeland Comfort Control (White Rodgers) Board Mount Limit Control 250F
The 3L09-17 Board Mount Limit Control (White-Rodgers / Copeland Comfort Control) is an automatic reset temperature safety switch designed to protect HVAC equipment, control boards, transformers, electric heaters, and electrical compartments from overheating. Featuring a 250°F fixed open temperature, this compact board-mounted bimetal limit switch interrupts the circuit when excessive temperatures are detected and automatically restores operation after cooling, helping protect critical electrical components and ensure reliable equipment performance.
Cross-Reference
- 3L09-17
- 3L0917
- L250F
- White-Rodgers 3L09-17
- Copeland Comfort Control 3L09-17
- 74T Series Board Mount Limit Control
Direct OEM
White-Rodgers 3L09-17
Compatible Brands
- White-Rodgers
- Emerson
- Copeland
- York
- Coleman
- Luxaire
- Goodman
- Rheem
- Universal HVAC Applications
Application
Used in HVAC and electrical equipment to:
- Protect control boards from overheating
- Interrupt safety circuits at elevated temperatures
- Automatically restore operation after cooling
- Protect transformers and electrical enclosures
- Safeguard electric heating components
- Prevent temperature-related component failures
Related Components
- Board Mount Limit Switch
- Snap Disc Thermostat
- Furnace Control Board
- Transformer
- Blower Relay
- High Limit Control
- Temperature Sensor
- Safety Cutoff Switch
- Electric Heat Control Assembly
Technician Notes
The 3L09-17 is an automatic reset, open-on-rise board mount limit control utilizing a compact bimetal sensing disc. Under normal operating conditions, the contacts remain closed and open when the sensing surface reaches 250°F, interrupting the circuit to prevent overheating. Once temperatures fall below the factory reset point, the contacts automatically reclose and restore operation.
Board-mounted limit controls are commonly used in electric heat assemblies, transformer protection circuits, electrical compartments, control boards, and OEM HVAC equipment where dependable high-temperature protection is required in a compact package.
Common Symptoms of Failure
- Equipment shuts down unexpectedly
- Open safety circuit faults
- Intermittent operation
- Repeated over-temperature shutdowns
- Electric heater lockouts
- Control board overheating faults
- No continuity through switch contacts
- Failure to reset properly
- Electrical compartment overheating
Installation Tips
- Disconnect power before servicing.
- Verify the replacement temperature rating matches the original control.
- Confirm switch action is Open on Rise.
- Mount securely in the original location.
- Inspect terminals for heat damage or corrosion.
- Verify adequate airflow around electrical components.
- Check continuity after installation.
- Test operation through a complete equipment cycle.
Recommended Inspection Items
- Control board condition
- Transformer temperature
- Wiring harness connections
- Electrical terminals
- Blower motor operation
- Airflow restrictions
- Electric heater elements
- Relay condition
- Ventilation around controls
- Equipment operating temperatures
Controls, Temperature, 250 degrees F Fixed Open Temperature, 225 degrees F Fixed Close Temperature, Open on Rise Switch Action, Auto Reset, 3.12" Insertion Length, Board Mounted 1/2" Bimetal Disc Limit Switch
