Series-AVFS

Supported Applications

The Dwyer Series AVFS Adjustable Air Flow Switch is designed to monitor air flow in ducts. It provides a contact output to indicate a change or loss of flow, complementing the line of thermo-anemometer transmitters and handheld instruments. The unit includes a mounting bracket for quick duct mounting and features a flush sensor design intended to limit issues due to dust or particulate in the air flow.

Operating Conditions & Performance

The series operates within an air velocity range of 197-1969 FPM (1-10 m/s) with a repeatability of ±5% FS. Process temperature limits are specified as 5 to 122°F (-10 to 50°C), and humidity limits are 0-90% RH. The maximum pressure rating is 14.7 psig (1 bar). Response time varies with flow and set point, ranging from 3-60 seconds.

Installation requires observing a minimum distance between the air flow monitor and bends or valves: MIN. 5xD upstream and MIN. 3xD downstream to avoid malfunction.

Configuration Options

The Series AVFS is offered in two power supply configurations:

• AVFS-1 (or AVFS-01): Powered by 80...250 AC/DC (47...63 Hz AC).
• AVFS-2 (or AVFS-02): Powered by 24 VDC ±25%.

The unit features a compact, rugged PBT enclosure rated NEMA 4X (IP65). Wetted materials consist of a PBT body and titanium sensor. The electrical connection is provided via a 6.5 ft (2 m) cable with brown, blue, black, and white wires.

Key configurable or fixed features include:

• Output Signal: 3 A contact output (N.O. SPST), rated at 30 VDC/250 VAC.
• Status Indication: Local status is indicated by a red LED and a green LED.
• Set-Point Adjustment: Includes an internal potentiometer to adjust the set-point.
• Housing Dimensions: 5-33/64 in [140.00] overall length, 29/32 in [23.00] diameter at housing end; probe insertion length is min. 1.25 in (32 mm) to max. 4.7 in (120 mm).
• Mounting: Includes a mounting clamp with a 0.9 in (24 mm) mounting hole diameter.

The unit carries CE approval and is not field serviceable; repair requires return to the manufacturer.

Key Product Differences

Variants within the Series AVFS differ primarily by power supply requirements. The AVFS-1 model supports 80...250 AC/DC (47...63 Hz AC), while the AVFS-2 model is configured for 24 VDC ±25%. Both models share identical measurement ranges, environmental ratings, output specifications, and physical dimensions.