Cleveland Control AFS-228-121 Switch

The Cleveland Controls AFS-228-121 is a professional-grade adjustable air pressure switch designed as a general-purpose proving switch for high-demand HVACR and energy management systems. This field-adjustable unit features a broad operating range of .05" to 12.0" w.c., providing technicians the flexibility to sense positive, negative, or differential air pressure across filters, coils, and fans. Engineered with a robust SPDT contact arrangement and a snap-acting switch mechanism, the AFS-228-121 supports 120-277Vac electrical loads, making it a versatile choice for package burners and furnace applications. The internal silicone diaphragm is specifically rated for air and combustion by-products, ensuring long-term reliability in harsh environments, provided the media does not degrade silicone. Built to withstand a 1/2 psi maximum pressure, this switch includes an integral mounting bracket and 1/4" quick-connect spade terminals for efficient field wiring. For precise calibration, technicians should utilize a digital manometer when adjusting the set point screw to maintain exact system specifications.

• Versatile Pressure Sensing: Capable of monitoring positive, negative, or differential pressure for various HVACR proving applications.
• Wide Adjustable Range: Field calibration from .05" to 12.0" w.c. allows for precise set point targeting in diverse air-handling environments.
• Reliable SPDT Output: The SPDT contact arrangement enables seamless integration into both alarm and control circuits.
• Industrial Durability: Features a high-quality silicone diaphragm and a plated housing for 100,000+ cycle performance with non-corrosive air media.
• Contractor Friendly: Standard 1/4" spade terminals and an easy-access adjustment screw simplify the HVAC air flow switch replacement process.

How do I calibrate the set point on the AFS-228-121?
To adjust the set point, turn the adjustment screw counter-clockwise until it stops, then turn it clockwise four full turns to engage the calibration spring. Use a digital manometer to verify the exact differential air pressure set point during system operation.

What mounting orientation is required for this switch?
For accurate operation at the lowest specified 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 or debris accumulation.

Can this switch be used to monitor flue gas?
Yes, the Cleveland Controls AFS-228-121 is compatible with combustion by-products that will not degrade the silicone diaphragm, making it suitable for many furnace and burner proving applications.

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.