McDonnell & Miller AF1-S Air Flow Switch

The McDonnell & Miller AF1-S Air Flow Switch is a paddle-type control that monitors air flow to ensure safe and efficient boiler and HVAC operation. It uses a SPDT snap switch for precise on/off signaling and features an adjustable sensitivity screw to tailor response to your system's air flow range.

Reliable performance is supported by a current rating of 7.4 A at 120 VAC and 3.7 A at 240 VAC, with an input supply rating of 125 VA at 120/240 VAC and 50/60 Hz. The switch handles temperatures from 32 to 300°F, making it suitable for challenging environments found in commercial and residential applications.

Built to meet UL and CSA standards, the AF1-S includes practical wiring features such as two electrical knock-outs for easier installation in control panels.

• Paddle-type air flow switch for accurate sensing
• SPDT snap switch for versatile signaling
• Sensitivity adjustable screw to fine-tune the switch
• Current rating: 7.4 A at 120 VAC / 3.7 A at 240 VAC
• Input supply rating: 125 VA at 120/240 VAC, 50/60 Hz
• Temperature range: 32–300°F
• UL and CSA listed for safety compliance
• Includes (2) electrical knock-outs for easy wiring