Dwyer AVFS-2 : Thermo Air Flow Switch, 24 VDC, Integral Red/Green Air Flow Status LED’s
The Series AVFS Adjustable Air Flow Switch enhances the Dwyer Instruments portfolio of thermo-anemometer transmitters and handheld devices. Engineered for monitoring airflow in ducts, the AVFS offers a 3A contact output to signal changes or losses in flow. Setting up the device is simple: power on the fan or air handling unit, then use the potentiometer to adjust the set-point to indicate normal operation. To test functionality, adjust a damper or reduce fan speed to trigger the AVFS. When airflow is lost, the AVFS activates the normally open (N.O.) SPST output, signaling the decrease.
For added convenience, the AVFS features a red/green LED indicator to show local status. A green light confirms airflow is above the set-point, while a red light signals airflow below the set-point. The device offers ±5% set-point repeatability over a range of 1-10 m/s (197-1969 fpm). Installation is quick with the included mounting bracket, ensuring secure duct placement.
The compact and durable PBT enclosure of the AVFS is NEMA 4X (IP65) rated, making it suitable for demanding ventilation system installations and other building automation system (BAS) applications.
Mounting Instructions:
- Use the provided mounting clamp to secure the airflow monitor. Ensure the mounting hole diameter is 0.9 in (24 mm).
- For an airtight seal, apply the included gasket.
- Fully immerse the sensing head into the airflow, ideally in the area with the highest velocity.
- Maintain an installation depth between 1.25 in (32 mm) and 4.7 in (120 mm) for optimal performance.
Specifications
| Air Velocity Range: | 197-1969 FPM (1-10 m/s). |
| Temperature Limits: | 5 to 122°F (-10 to 50°C). |
| Humidity Limits: | 0-90% RH. |
| Wetted Materials: | PBT body, titanium sensor. |
| Pressure Limit: | 14.7 psig (1 bar). |
| Housing: | PBT. |
| Repeatability: | ±5% FS. |
| Switch Type: | N.O. SPST. |
| Electrical Rating: | 3 A @ 30 VDC/250 VAC. |
| Response Time: | 3-60 s. Varies with flow and set point. |
| Power Requirement: | AVFS-2: 24VDC ±25%. |
| Power Consumption: | 3 VA. |
| Electrical Connection: | 6.5´ (2 m) cable. |
| Enclosure Rating: | IP65. |
| Display: | 1 red LED/1 green LED. |
| Weight: | 7.2 oz (203 g). |
| Compliance: | CE. |
Datasheets
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Dwyer AVFS | Thermo Air Flow Switch Data Sheet |
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Dwyer AVFS | Thermo Air Flow Switch Installation and Operating Instructions |
