The Cleveland Controls AFS-398 is a professional-grade air pressure sensing switch engineered for precision proving in HVAC and energy management systems. This differential air pressure switch features a versatile adjustable set point range from 0.03" to 2.0" w.c., allowing for exact field calibration using the integrated adjustment screw. This SPDT air switch is housed in a rugged plated enclosure with a high-quality silicone diaphragm, making it compatible with air and typical combustion by-products. The AFS-398 is optimized for sensing positive, negative, or differential pressure in furnaces and package burners. Its snap-acting SPDT switch contacts are rated for 15 Amps non-inductive, ensuring reliable performance in demanding contractor applications. For secure integration, the unit includes two male 7/16"-24 UNS 2A threaded sample line connections with nuts and ferrules, plus a 7/8" conduit opening to simplify field wiring. Key Benefits for Technicians Broad Set Point Versatility: Field-adjustable "Operate Range" of 0.05" to 2.0" w.c. provides flexibility across various equipment models. Rugged Construction: Plated housing and silicone diaphragm withstand operating temperatures from -40°F to 180°F. Reliable Switching: 100,000 cycle minimum lifespan at 0.5 psi maximum pressure ensures long-term system stability. Easy Installation: Built-in surface mounting bracket with 3-7/8" spacing and barbed/threaded options for 1/4" OD sample lines. Safety Focused: Enclosure cover protects live terminals and set point adjustments from accidental contact. Common Questions & Technical Support How do I calibrate the set point? Use a digital manometer to verify the set point at the unit's actual operating temperature. Turn the adjusting screw counterclockwise until motion stops, then turn four full rotations clockwise to engage the spring before fine-tuning. What mounting orientation is required? The diaphragm must be mounted in a vertical plane to achieve the lowest specified operating set point. Avoid mounting with sample line connections pointing upward to prevent moisture or debris accumulation. Can this switch handle both positive and negative pressure? Yes. Connect positive pressure lines to the "H" inlet and negative/vacuum lines to the "L" inlet. For differential sensing, connect both ports to monitor the drop across filters or coils. 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.
