Reznor 123973 Limit Switch

The Reznor 123973 Limit Switch is a critical OEM replacement component engineered for precise thermal regulation within Reznor unit heaters and furnace systems. This 105-160F AUTO Fan & Limit Control functions as a high-limit safety device, automatically cycling the blower fan and interrupting the burner circuit if internal plenum temperatures exceed safe operating parameters. Designed for professional HVAC equipment repair, the 123973 ensures proper airflow management and prevents heat exchanger fatigue caused by overheating. As a genuine Reznor replacement part, it features a factory-calibrated bimetal sensor for consistent response times. Whether you are performing routine maintenance or troubleshooting a furnace limit switch tripping issue, this high-limit safety switch provides the exact electrical specifications and mounting configuration required for Reznor HVAC systems, maintaining the integrity of the original equipment's safety string without the risks associated with universal aftermarket alternatives.

Key Benefits for Contractors

• Precise Thermal Calibration: Fixed 105-160°F range ensures accurate fan cycling and high-limit protection for Reznor unit heaters.
• Direct OEM Fit: Eliminates the need for field modifications, ensuring 123973 fan control compatibility with existing wiring harnesses.
• Automatic Reset: Features a 105-160F AUTO reset function that restores operation once the system cools to safe levels.
• System Longevity: Prevents excessive heat buildup, protecting the heat exchanger and critical HVAC furnace components.

Common Questions

Is the Reznor 123973 compatible with universal fan limit controls?
While some universal controls exist, the Reznor 123973 is specifically calibrated for the static pressure and thermal profiles of Reznor units. Using the genuine OEM part is recommended to ensure the safety circuit operates within factory parameters.

What causes a Reznor limit switch to trip repeatedly?
Frequent tripping of the high-limit safety switch usually indicates restricted airflow, such as a clogged filter, a failing blower motor, or an oversized gas valve setting. Always verify temperature rise across the heat exchanger when replacing this limit control.

Does this switch require manual resetting?
No, this is an automatic fan limit switch. It will reset itself once the temperature drops below the 105°F threshold; however, if it trips frequently, the underlying heating issue must be addressed by a technician.

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.