In Duct Digital Psychrometers and Hot-Wire Anemometer

Now HVACR Technicians Can Take CFM, %RH, Wet Bulb,and Dry Bulb Measurements Where They Should – In the Duct.

Four New Fieldpiece Products Feature 38” Telescoping Probe thatReaches Inside for Proper Location and Placement.


January 23, 2012 Anaheim, Calif. – Fieldpiece Instruments introduces its new line of In-Duct HVACR instruments featuring an expandable 38” telescoping probe making it easier to take temperatures, %RH, wet bulb, or air velocity readings at the correct location—in the duct for more accurate results.

The four new in-duct products include two psychrometers (SRH3 and ARH5), one hot-wire anemometer (STA2), and a combination of both the hot-wire anemometer and psychrometer in one (AAT3). The standalone STA2 hot-wire anemometer uses a hot wire for measuring air velocity, and can automatically average multiple air velocity measurements for traversing, and for minimizing the effects of turbulence. It also automatically averages multiple test points based on the free area input to calculate CFM, so techs get the same results without the hassle of costly and bulky hoods.

In addition to being a hot-wire anemometer, the AAT3 accessory head is also a psychrometer so not only is it useful for air balancing like the STA2, but it also measures %RH and dry bulb, and calculates wet bulb and dew point.

“Both hot-wire anemometers help technicians provide a more thorough system diagnosis because they can measure air velocity at the correct location in the duct, and calculate CFM,” said Russ Harju, product manager. “Techs know immediately if the system is pushing the air it’s supposed to. If there’s a problem with air flow, techs can quickly determine if it’s the unit, or the duct work that’s the culprit.”

The psychrometers come in a standalone (SRH3) and accessory head (ARH5) version, and feature both %RH and temperature sensors to display %RH, wet bulb, dry bulb, and dew point. The standalone SRH3 takes it a step further and uses these measurements to calculate target superheat, and target evaporator exit temperature to help technicians better diagnose a system.

The AAT3 and ARH5 accessory heads attach directly to any Fieldpiece stick meter, or can be used wirelessly to send remote measurements to the new line of Fieldpiece wireless meters.

“Our new accessory heads are a great complement to our new wireless meters,” said Harju. “They send wet and dry bulb measurements wirelessly to the meters so techs can make adjustments at the condenser while receiving live temperature readings from the attic, or wherever the evaporator is located,” said Harju.

All four in-duct products feature a slim probe (less than 3/8” in diameter) with laser etching that shows both inches and centimeters so technicians know exactly how far the probe is inserted into the duct. Additionally, the probe has flat sides to indicate when the sensor is correctly facing the air steam, ensuring the air is moving over the sensor at the proper angle. The probe retracts down to 11” for storage and extends out to 38” inches for larger ducts. For hands-free testing, the included cone holds the probe in place while it is extended into the center of the ductwork.

“The in-duct products make it easier to do installations and repairs the right way because the measurements are taken exactly where they’re supposed to be taken – with the sensor in the duct,” stated Harju.

The in-duct products are available immediately. Suggested trade prices are $349.00 for the STA2 (Hot wire, averaging, display three parameters at once) $199.00 for the AAT3 (Hot wire + RH%); $179.00 for the SRH3 (RH% + diagnostics); $129.00 for the ARH5 (RH%. They can be purchased from a Fieldpiece distributor near you.

Client Contact: Russell Harju – Product Manager, (714) 634.1844
Press Contact: Beverly Steinberg, (714) 777-2760


Formed in 1989, Orange County, Calif.-based Fieldpiece Instruments has become the testing tool company that HVACR professionals trust. Because Fieldpiece focuses only on the HVACR industry, all products are developed to solve real world HVACR problems. Not only do the tools have the right functions and features, but also techs can trust them to work where and when they need them, because they withstand the use and abuse techs in the HVACR field dish out. Fieldpiece constantly develops new tools that allow HVACR professionals to do more than they otherwise could, increasing the tech’s capability and billable hours. For more information please visit our website at or call 714.634.1844.

  • Created: Thu, January 17, 2013