Johnson Controls AFS-222 Sensing Switch

The Johnson Controls AFS-222 Sensing Switch is the direct performance-grade update for legacy A/AFS222 and L-200-RH3 models. Engineered specifically for high-demand HVACR and energy management applications, this differential air pressure switch features a versatile set point range of 0.05" ? 0.02" to 12.0" w.c., making it ideal for monitoring positive, negative, or differential pressure across coils and filters. The unit is housed in a rugged zinc-plated steel enclosure that protects the SPDT contact arrangement and silicone diaphragm from the mechanical stresses of a mechanical room environment.

For contractors, the AFS-222 provides a reliable solution for proving airflow in safety circuits or automation loops. The 1/4" OD sample line connection utilizes a compression ferrule and nut system to ensure leak-free performance even at its 0.5 psi maximum pressure limit. With a switching differential that progressively increases from 0.02" to 0.8" w.c., this adjustable air pressure sensing switch delivers precise control without the nuisance tripping often associated with fixed-rate alternatives. Designed to handle air and common combustion by-products, it integrates seamlessly into existing ductwork using the standard two-hole mounting bracket.

• Broad Compatibility: Serves as a versatile HVAC air flow switch replacement for obsolete A/AFS222 and L-200-RH3 components.
• Field Adjustability: Features an accessible set point screw for calibration between 0.05" and 12" w.c. to meet specific system static pressure requirements.
• Industrial Durability: Rated for over 100,000 cycles at maximum electrical load, ensuring long-term fan proving switch reliability.
• Secure Interfacing: The 7/8" conduit opening and screw-top terminals with cup washers facilitate rapid, code-compliant wiring.

How do I adjust the set point on the AFS-222?
To calibrate, turn the adjusting screw counterclockwise until it stops, then turn four full rotations clockwise to engage the spring. Each subsequent full turn represents approximately 1.2" w.c. We recommend using a digital manometer for final verification.

Can this switch be used in dirty air environments?
Yes, the Johnson Controls AFS-222 is rated for air and combustion by-products that do not degrade silicone. However, ensure the sampling probe is mounted at least 1.5 duct diameters downstream of the air source for the most stable readings.

Does mounting orientation affect performance?
Yes. To achieve the lowest specified operating set point, the switch must be mounted with the diaphragm in a vertical plane. Avoid mounting with the sample line connections facing upward to prevent moisture accumulation.

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.