Sterling HVAC 11J11R00306-002 Limit Switch

The Sterling HVAC 11J11R00306-002 is a high-limit safety control designed for precise thermal monitoring in gas-fired unit heaters. This OEM limit switch operates on a 170-40F logic, meaning it is engineered to open the electrical circuit at a 170°F temperature rise and automatically reset upon a 40°F drop (closing at 130°F). As a critical furnace safety switch, it prevents heat exchanger damage by interrupting the gas valve circuit if internal temperatures exceed safe operating parameters. Professionals typically find this L170-40F switch in Sterling QV, TF, and MS series heaters, where reliable HVAC part replacement is essential for maintaining equipment uptime. The disc-style construction ensures rapid thermal response, while the automatic reset capability eliminates the need for manual intervention once the unit cools. This 170 degree limit switch is a direct replacement for part number 11J11R00306-002, featuring standard 1/4-inch terminals for a secure, low-resistance connection in 24V or line voltage control circuits.

• Precise Thermal Trip Point: Calibrated to open at 170°F with a ±10°F tolerance to protect heat exchangers from cracking.
• Automatic Reset Logic: The 130-170F Auto Limit Switch re-engages the circuit automatically at 130°F, ensuring the heater resumes operation without a service call once airflow is restored.
• Wide Series Compatibility: Fits a broad range of Sterling HVAC unit heaters, including QVSF, QVSB, QVF, and TF series models from 100 to 400 MBH.
• Durable Construction: Features a rugged disc-style sensor and high-grade OEM specifications for consistent performance in high-cycle commercial environments.
• Simplified Field Replacement: Designed with standard mounting footprints and terminal locations to streamline HVAC repair tasks for contractors.

How do I troubleshoot a Sterling 11J11R00306-002 switch?
If the burner shuts down while the thermostat is calling for heat, check for continuity across the switch terminals while the unit is cool. An open circuit at room temperature indicates a failed high limit control that requires replacement.

What causes this limit switch to trip repeatedly?
In most cases, a furnace limit switch trips due to restricted airflow. Verify that the air filters are clean, the blower motor is operating at the correct RPM, and that no supply or return vents are obstructed.

Is the 11J11R00306-002 an automatic or manual reset switch?
This specific model is an automatic reset limit switch. It will close the circuit on its own once the temperature drops below the reset threshold (130°F), unlike manual reset switches that require a physical button press.

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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.