The Reznor 100799 Limit Control is a critical safety component designed for precise thermal regulation within Reznor unit heaters. This L150-25F high-limit switch operates with a fixed temperature setpoint, featuring an open-on-rise configuration at 150°F and a 25°F differential for reset. Engineered for rapid response to heat exchanger over-temperature conditions, this SPST limit switch ensures the burner circuit is interrupted if airflow is restricted or if the HVAC blower motor fails. This OEM replacement part is essential for maintaining the safety sequence of operation in commercial gas-fired heaters and industrial unit heaters. Its robust construction resists vibration and high-heat cycles common in ceiling-mounted equipment. When diagnosing furnace limit trips, technicians should verify the 100799's continuity to ensure reliable furnace cycling and prevent premature component fatigue. This thermal cutout switch is a direct drop-in for several Reznor venting and heating systems requiring a 150-degree limit control. Key Benefits: Precise Thermal Callibration: Engineered with a 150°F trip point to protect the heat exchanger from thermal stress. Fast Reset Response: The 25°F differential ensures the system returns to operation quickly once safe temperatures are restored. Direct OEM Compatibility: Ensures seamless integration with existing Reznor wiring harnesses and mounting brackets. Electrical Reliability: Designed for high-cycle industrial use with clean SPST contact breaking. Common Questions: What causes a Reznor 100799 limit switch to trip frequently? Frequent tripping is usually indicative of restricted airflow, such as a blocked return, a failed blower motor, or a malfunctioning fan belt. If the switch remains open when the unit is cool, the internal bimetal disc may have failed. Can I use an L175 switch instead of the L150-25F? No. Using a higher temperature limit can compromise the safety of the heat exchanger and void the equipment's UL certification. Always match the specific temperature ratings of the 100799. Is this a manual or automatic reset switch? The Reznor 100799 is an automatic reset limit control, meaning it will close the circuit once the plenum temperature drops 25°F below the 150°F trip point. 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.
