Fieldpiece: Psychrometers, Hot-Wire Anemometer
May 21, 2012
With the 38-inch telescoping probe, a line of in-duct HVACR instruments — two psychrometers (SRH3 and ARH5) and a hot-wire anemometer (STA2) — makes it easier for techs to take temperature, percent rh, or air velocity readings in the duct. The standalone STA2 uses a hot wire for measuring air velocity. It displays any combination of cfm, air velocity, and temperature at the same time on the backlit dual display. The instrument 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, claimed the manufacturer. The psychrometers feature a percent rh sensor and a thermistor to display percent rh, wet bulb, dry bulb, and dew point. The SRH3 standalone uses these measurements to calculate target superheat, and target evaporator exit temperature, to help technicians better diagnose a system. The ARH5 accessory head attaches directly to any of the company’s stick meters, or can be used wirelessly to send remote measurements to the manufacturer’s line of wireless meters. All three units feature a probe that shows both inches and centimeters so techs 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 airstream, ensuring the air is moving over the sensor at the proper angle.