Cleveland Controls AFS-405-121 Switch

The Cleveland Controls AFS-405-121 is a professional-grade air pressure sensing switch specifically engineered for HVAC, DDC, and energy management proving circuits. This field-adjustable unit features a broad operating range of 0.05" w.c. to 12.0" w.c., making it a versatile solution for sensing positive, negative, or differential air pressure across filters, coils, and fans. To ensure reliable performance in low-current and computer-interface applications, the AFS-405-121 is equipped with gold-clad SPDT contacts, preventing oxidation and ensuring signal integrity where standard silver contacts might fail. The housing is constructed from rugged plated steel, protecting the silicone diaphragm and calibration spring from industrial wear. Installation is streamlined with 1/4" OD compression fittings and a 1/2" conduit entry. For accurate field calibration, the progressive switching differential ensures precision throughout the scale, making this the standard for contractors requiring an adjustable pressure switch that integrates seamlessly with modern building automation systems.

• Enhanced Signal Reliability: High-performance gold-plated contacts allow for low-voltage/low-current switching, ideal for direct digital control (DDC) integration.
• Broad Pressure Adaptability: The wide adjustment range from 0.05 to 12 inches water column eliminates the need for multiple SKUs on the service truck.
• Versatile Media Sensing: Capable of monitoring static pressure, differential pressure, or vacuum in both air and non-combustible gas environments.
• Industrial Build Quality: Zinc-plated steel enclosure and silicone diaphragm withstand temperature extremes from -40°F to 180°F.

How do I adjust the set point on the AFS-405-121?
Remove the metal enclosure cover and turn the adjustment screw clockwise to increase the set point or counterclockwise to decrease it. For precision calibration, use a digital manometer to verify the "make" and "break" points during commissioning.

Can this switch be mounted in any orientation?
For maximum accuracy at the lowest set points, the AFS-405-121 must be mounted with the diaphragm in a vertical plane. Avoid mounting with the sample line connections pointing upwards to prevent moisture or debris from accumulating on the diaphragm.

What is the maximum electrical load for this SPDT switch?
The unit is rated for 300 VA pilot duty at 115 to 277 VAC and 15 amps non-inductive at 277 VAC, providing significant overhead for most HVAC control circuits.

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.