A 24 VDC thermal air flow switch for duct monitoring, covering 197–1969 FPM with a titanium sensor and IP65 enclosure.
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Part No. AVFS-2
The Dwyer AVFS-2 monitors duct air flow using thermal dispersion sensing rather than a moving paddle, providing a solid-state alternative for installations operating from 24 VDC control power. It covers a full-scale velocity range of 1–10 m/s (197–1969 FPM) and provides ±5% set-point repeatability.
The switch provides a 3 A N.O. SPST contact output when airflow drops below the set trip point. A titanium thermal sensor housed in PBT provides corrosion-resistant construction, while the IP65 enclosure helps protect the electronics from duct-side dust and moisture.
Installation is straightforward, with a mounting bracket for positioning the switch in the duct and a 6.5 ft (2 m) cable for connection to the control panel. Its 3–60 second response time is suitable for typical fan-proving and duct airflow interlock applications.
Need a different specification? The Dwyer range also includes the AVFS-1, an 80–250 VAC/DC thermo air flow switch, so you can select the model that matches your available control power.
Ready to order the AVFS-2? Speak to our team. Call +971 6 5436933.
Key Benefits
- Solid-state thermal sensing with no moving paddle
- 197–1969 FPM (1–10 m/s) full-scale air velocity range
- 24 VDC ±25% power supply for dedicated low-voltage control systems
- Titanium sensor in a PBT housing for corrosion-resistant construction
- IP65 enclosure for protection against duct-side dust and moisture
- 3 A N.O. SPST contact output
- ±5% set-point repeatability
- 3–60 second response time for airflow monitoring and fan-proving applications
Who This Product Is Best For
- HVAC controls contractors working with 24 VDC control systems
- Building automation and air-handling system installers
- Technicians installing fan-proving or duct airflow interlocks
- Maintenance teams requiring a low-maintenance thermal airflow switch
- Applications where a solid-state alternative to a mechanical paddle switch is preferred
How to Use
- Mount the AVFS-2 in the duct using the supplied mounting bracket.
- Position the thermal sensor correctly in the airflow path.
- Connect the 24 VDC ±25% power supply and route the 2 m cable back to the control panel.
- Set the required airflow trip point according to the application.
- Verify that the switch responds correctly within the specified 3–60 second response time.
- Confirm that the 3 A N.O. SPST contact operates correctly at the intended trip point.
Frequently Asked Questions
What power supply does the AVFS-2 require?
The AVFS-2 operates from a 24 VDC ±25% power supply.
What is the AVFS-2's air velocity range?
It covers 197–1969 FPM, equivalent to 1–10 m/s, full scale.
What type of sensor does the AVFS-2 use?
It uses a titanium thermal dispersion sensor housed in PBT.
What is the enclosure rating?
The AVFS-2 has an IP65-rated enclosure for protection against dust and moisture.
What type of output does the AVFS-2 provide?
It provides a 3 A N.O. SPST contact output.
How quickly does the AVFS-2 respond?
The specified response time is 3–60 seconds.
Is the AVFS-2 suitable for fan-proving applications?
Yes. Its airflow sensing and 3–60 second response time make it suitable for typical fan-proving and duct airflow interlock applications.
Is the AVFS-2 CE approved?
Yes, the supplied product information states that the AVFS-2 carries CE approval.
What's the difference between the AVFS-2 and AVFS-1?
The AVFS-2 is designed for 24 VDC power, while the AVFS-1 is the 80–250 VAC/DC version for installations requiring a mains-range supply.
Does GeneralTech Shop deliver the AVFS-2 across the UAE?
Call +971 6 5436933 and our team will confirm delivery availability and timelines for your emirate.
Should I choose the AVFS-2 or AVFS-1?
The AVFS-2 is intended for systems with a dedicated 24 VDC supply, while the AVFS-1 is designed for applications using 80–250 VAC/DC power.
For pricing or to place an order, contact GeneralTech Shop. Call +971 6 5436933.
