Dwyer Series AVU Air Velocity Transmitter

Product Description

The Series AVU Air Velocity Transmitter is ideal for a wide range of HVAC measurement and control applications, particularly in complete building control and energy management systems. The Series AVU is available with 5% or 8% accuracy at a surprisingly low cost, with 9 models covering ranges from 0-785 FPM to 0-3150 FPM, with either 4-20 mA or 0-10 VDC output.

The Series AVU Transmitter operates by measuring the heat loss from one of the two sensing elements in the air stream, then calculating the air velocity. Units are virtually immune to drift due to the design of the sensing element, which makes the transmitter accurate over the whole air velocity range.

Product Applications

• Supply and exhaust fan
• Clean room systems
• Air pollution studies and manufacturing
• Process control systems

Models

Specifications

Service:

Clean air and compatible, non-combustible gases.

Accuracy:

AVU: ±5% of full-scale;
AVUB: ±8% of full-scale.

Response Time (90%):

5 sec (typical).

Temperature Limits:

32 to 122°F (0 to 50°C).

Humidity Limit:

0-90% RH, non-condensing.

Power Requirements:

-A models 24 VDC +10% – 15%; -V models 24 VDC or 24 VAC +10% – 15%.

Output Signal:

-A models 4-20 mA current loop; -V models 0-10 VDC.

Loop Resistance:

(-A models ) 700 Ω.

Current Consumption:

60 mA + output current.

Maximum Start Up Current:

85 mA; 10 V.

Output Current Limit:

(-V models) >10 mA.

Electrical Connections:

Screw terminal. Cable gland for 4-8 mm wire (16 gage wire).

Enclosure Rating:

NEMA 6 (IP67) except sensing point.

Probe Dimensions:

9.45 x .75″ (240 x 19 mm).

Mounting Orientation:

Unit not position sensitive. Probe must be aligned with air flow.

Weight:

8.8 oz (250 g).

Agency Approvals:

CE.

Features

• 4-20 mA or 0-10 V Output Versions
• NEMA 6 (IP67) Enclosure Rating
• AC or DC Powered (Loop Version DC Only)
• 5% or 8% Accuracy

Literature

Manuals

AVU
AVUB

Catalog Pages

Series AVU Catalog Page

Drawings

AVU .dwg
AVU .pdf
AVUB .pdf
AVUB .dwg

Accessories

FAQ

Question

We have recently replaced a Dwyer air velocity transmitter (PFS1300204) with a Dwyer Series 641. The new sensor works fine for only a few days and then starts reading almost no flow. These devices are used in an Air Scrubber application (exhaust stack). Is this the right application for the Series 641? I suspect that moisture might be the issue, but I cannot confirm.

Answer

I do not think you are using the 641 series air velocity transmitter in an appropriate application. Any moisture or particulates in the exhaust could be causing damage to the hot wire sensor, leading to the failure. The difference in the sensors is probably why you got longer life out of the PFS series, which unfortunately, is no longer available. The PFS series used a glass filled polyester sensor, which is a little more robust and can with stand the elements a little better. In your specific application, you might take a look at our 641B series which uses a heated mass flow sensor which can be used in dirty air environments.

Related

Series 641RM

Model 641B

Series AVU

Series 641