The Cleveland Controls DFS-221-153 is a precision-engineered airflow proving switch designed for critical monitoring in duct heaters, commercial ovens, and high-demand HVAC systems. This differential air pressure sensing switch features a factory-fixed setpoint of 0.05" W.C., making it an ideal choice for applications requiring a non-adjustable, tamper-proof safety control. Built with a robust zinc-plated housing and a high-performance silicone diaphragm, it reliably senses positive, negative, or differential pressure in air or non-corrosive combustion by-products. The unit is equipped with a standard SPDT contact arrangement, rated for up to 277 VAC, ensuring seamless integration with most building automation and energy management controllers. This specific model, the DFS-221-153, includes 0.25-inch barbed connections for secure attachment to flexible tubing and is designed for surface mounting in tight spaces where internal access is restricted. To maintain accuracy, always mount the diaphragm in a vertical plane to prevent setpoint drift caused by gravitational influence. Key Benefits for the Contractor Fixed Setpoint Reliability: Pre-set at 0.05" W.C. to eliminate field adjustment errors and ensure consistent safety interlocking. Versatile Media Compatibility: Capable of sensing air and various combustion by-products without compromising the silicone diaphragm. High Electrical Capacity: The SPDT snap-action switch handles up to 15 amps non-inductive, providing flexibility for pilot duty or direct load switching. Compact Footprint: Specifically engineered for surface-mounting in areas with limited internal clearance. Industrial Durability: Rated for up to 100,000 cycles at maximum pressure, ensuring longevity in commercial environments. Common Questions & Technical Support What is the maximum pressure rating for this switch? The DFS-221-153 is rated for a maximum pressure of 0.5 psi (approximately 13.85" W.C.), making it suitable for standard low-pressure duct environments. Can I use this switch for negative pressure sensing? While this specific model is noted for no neg# fitting (typically referring to the secondary port configuration on certain variations), the DFS-221 series generally supports differential sensing. However, users should verify the specific porting on the 153-suffix model to ensure it meets their vacuum or pressure-side requirements. In what orientation should the switch be installed? For maximum precision and to meet the 0.05" W.C. specification, the switch must be mounted with the diaphragm in a vertical plane. Horizontal mounting will cause the setpoint to shift due to the weight of the diaphragm. This item is not eligible for free shipping. 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.
