Belimo NFB24 MFT Actuator 318172 701 ensuring the furnace high limit ensuring the furnace high limit operates within strict manufacturer tolerances to maintain system integrity and safety during high demand heating cycles Field technicians should verify the negative pressure reading at the tap to confirm the SP11875 is the correct exhaust pressure switch for the specific model's airflow requirements Key Benefits Universal Compatibility: Programmable MFT technology allows one actuator to adapt to various control signals and applications the direction of the fail safe is determined by which side of the actuator is mounted to the shaft