Series 641RM: For Remotely Mounting Electronic Enclosure Air Velocity Transmitter with Remote Probe connects the sensing probe with the electronic enclosure allowing the enclosure to be mounted where it can be accessed.

Model 641B: Dirty Air Flow Applications Air Velocity Transmitter is used for dirty air flow applications. Applications include clean room ventilation monitoring, fan supply, and exhaust tracking.

Series AVU: Ideal for Building Automation Systems, ±5% or ±8% Full Scale Accuracy Air Velocity Transmitter ideal for a wide range of HVAC measurement and control applications. Applications include zone control in HVAC systems and clean room systems.

Series 641: High Accuracy, Field Selectable Ranges Air Velocity Transmitter is ideal for monitoring air flow. Optional LED produces complete, low cost solutions for local indication of air flow.

Series AVUL: 3% and 5% of Reading Accuracy Air Velocity Transmitter accurate and available for a variety of needs. Measures air velocity and volumetric flow.

Series AVLV: 1% and 2% Models, Optional BACnet MS/TP or Modbus® Air Velocity Transmitter quickly and accurately measures air velocity or volumetric flow in imperial or metric units.

Series AVPT: 3% and 5% Models, Optional BACnet Communication Protocols Pencil Style Air Velocity Transmitter uses thermal anemometer technology to provide high accuracy and stable air velocity measurements in imperial and metric units

Questions

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 641

Question

Can you use a display with the Modbus or BACnet options?

Answer

Yes, either the integral LCD Display, A-AVUL-LCD, or the remote display tool, A-435-A, can be used with Modbus or BACnet configurations.

Related

Series AVUL

Question

Is there a minimum duct size that this sensor can be used in?

Answer

The sensing element is about ¾” from the tip of the stem so the duct size would need to accommodate the entire sensing element. If being used in a smaller duct, you will want to verify that the flow range is within the operating range, 1000, 2000, 3000, or 4000 FPM.

Related

Series AVUL

Question

Can the AVPT output volumetric flow readings

Answer

No, the AVPT is configured to output air velocity readings in FPM or M/S only. Consider looking at the AVUL for a unit able to output volumetric air flow.

Related

Series AVPT

Series AVUL

Question

Are there any advantages to using a BACnet model other than the communications output?

Answer

When purchased with the BACnet communication option, the AVPT can display both the air velocity reading and temperature reading from a single device minimizing the need for an additional temperature sensor in the duct.

Related

Series AVPT

Videos

Thermo-Anemometers

Air Velocity Transmitter: Series AVUL

Series AVUL Air Velocity Transmitter