The Reznor 164792 Limit Switch is a critical safety component designed for high-limit protection in unit heaters and industrial HVACR systems. As a genuine Reznor OEM replacement part, this L300F high limit switch is engineered to monitor heat exchanger temperatures and interrupt the burner circuit if conditions exceed a safe thermal threshold of 300°F. This specific model features a 54-inch capillary tube, providing the necessary reach for precise bulb placement in the airstream of large-capacity units. The Reznor 164792 is an auto-reset limit switch, allowing the system to resume normal operation once temperatures drop below the trip point, provided no underlying mechanical failure exists. For technicians performing maintenance or emergency repairs, the 164792 is the direct replacement for 211066. Utilizing factory-authorized heating parts ensures exact HVAC compatibility, maintaining the precise electrical ratings and response times required to protect the heat exchanger from cracks or premature fatigue. Key Benefits for Contractors: OEM Precision: Direct factory match for legacy part 211066, eliminating mounting and wiring modifications. Extended Reach: Includes a 54-inch capillary for flexible routing and optimized sensing in high-clearance cabinets. Thermal Protection: Calibrated L300F (300°F) trip point provides a reliable safety barrier against overheating. Automatic Reset: Reduces nuisance service calls by automatically cycling back once the heat exchanger cools. Application Versatility: Common in Reznor RDH, PDH, and UDX series heaters requiring high-temperature safety cutouts. Common Questions: What causes a Reznor limit switch to trip repeatedly? Frequent tripping usually indicates restricted airflow, often due to a dirty blower wheel, clogged air filters, or a failing fan motor. If the unit remains in high-limit lockout, verify that the 54-inch capillary bulb is properly seated in the discharge air path and not touching the heat exchanger directly. Can I use a universal limit switch instead of the 164792? Standard universal switches often lack the specific 54-inch capillary length or the precise 300-degree trip calibration required for Reznor equipment. Using the genuine Reznor 164792 ensures the safety circuit operates exactly as the manufacturer intended. How do I verify if my 211066 switch needs replacement? Check for continuity across the terminals when the unit is cool. If the switch remains open at room temperature, or if the capillary tube shows signs of kinking or leakage, a replacement is necessary to restore safe heater operation. 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.
