AFS-460-DSS Johnson Controls Air Flow Switch

Overview

The Johnson Controls AFS-460-DSS is a general-purpose, manual-reset air pressure sensing switch designed to prove airflow and monitor differential pressure in HVAC and building automation applications. It is engineered for systems requiring dual manual reset switches with SPST contacts, allowing it to sense positive, negative, or differential air pressure within commercial environmental control configurations. The plated housing contains a diaphragm, calibration spring, and two snap-acting switches with a single manual reset button on the top surface.

Features

• Dual sensing switches featuring a lead snap switch and a lag snap switch for staged actuation
• Manual reset functionality requiring operator interface to close the switch following actuation
• Dual SPST normally closed (NC) contact arrangement
• High-impact protective enclosure cover that guards against accidental contact with live switch terminal screws and the setpoint adjusting screw
• Enclosure cover designed to accept two 0.5-inch conduit connections
• Vibration-resistant mounting capability allowing installation in any vertical plane to maintain low setpoint accuracy

Specifications

• Field Adjustable Setpoint Range: 1.25 inches to 12.0 inches W.C. (with lead switch adjusting screw calibration)
• Maximum Pressure Rating: 0.5 psi (0.03 bar, 3.45 kPa)
• Electrical Rating: 15 A at 125, 250, or 277 VAC; 1/4 hp at 125 VAC; 1/2 A at 125 VDC; 1/4 A at 250 VDC; 0.5 VA at 24 VAC (50/60 Hz)
• Operating Temperature Range: -40°F to 180°F (-40°C to 82°C)
• Electrical Connections: Screw terminals with cup washers
• Sample Line Connections: Ferrule and nut compression connectors accepting 0.25-inch OD rigid or semi-rigid tubing
• Sample Media: Air or combustion products that do not degrade silicone
• Mechanical Endurance Life: Exceeds 6,000 cycles minimum at maximum pressure and load
• Approvals: UL and CSA approved

Applications

• Proving fan status and airflow verification in sensitive ventilation systems
• Monitoring HVAC filters for excess pressure drop
• Monitoring duct static pressure in commercial zoning systems
• Monitoring commercial damper status
• Energy management applications requiring manual operator intervention following safety limit trips