Engineered Systems Magazine

Psychrometers: Fieldpiece Instruments

April 29, 2013

Fieldpiece-042913-body.jpgThe Dual In-Duct SDP2 measures two return temps and two supply temps – at the same time.

The new Dual In-Duct Psychrometer from Fieldpiece Instruments is the first of its kind to measure both supply and return air conditions at the same time and adjusts calculations based on changing conditions. Designed for HVACR professionals, the standalone psychrometer has two probes that each simultaneously measures wetbulb and drybulb (temp) at both the return and supply to provide live readings of the evaporator conditions.

In addition, data can be sent wirelessly to the Fieldpiece SMAN4 Digital Manifold for live target superheat calculations while working at the condenser, or to the HG3 System Analyzer for full system analysis and data reporting.

One probe is placed in the duct before the evaporator (RETURN) and one placed after the evaporator (SUPPLY). These four measurements can be displayed or used in calculations to display the actual temperature split (delta T), the target temperature split, the actual evaporator exit temperature, or the target evaporator exit temperature (TEET), plus the difference between the actual and target. Enthalpy (BTU/LBM) and Dew Point can also be displayed.

         The TEET takes into consideration the latent heat used to condense water from the air, while a simple 20° temperature split ignores latent heat. TEET, developed by Fieldpiece, is better. Plus, it’s easier in the field to aim for a single value (TEET) than the difference between two changing values.

“Techs are used to doing Delta T with two drybulbs,” said Russ Harju, Fieldpiece product manager. “The SDP2 adds two wetbulb measurements, so HVACR professionals can dial in evaporator performance because they’re making decisions based on four live, dynamic measurements.”   

The wireless feature further enhances technicians’ capabilities because the SDP2 works together with both the SMAN4 and the HG3 System Analyzer.  These three products equal a full HVACR wireless system analysis. The HG3 performs all the calculations from the four indoor measurements from the SDP2 and five outdoor measurements from the SMAN4.

  The SDP2 is also a key ingredient in completing the Fieldpiece HVACR wireless system.  With three powerful tools (the SDP2 with the SMAN4 Manifold and HG3 System Analyzer) technicians can do a full system analysis (9 live readings) with easy to understand diagnostics.  All tests are viewable on the HG3 so technicians can easily explain the system and its problems to customers.  And all the data can be downloaded for billing and documentation.”

The SDP2 is easy to setup and read. The 38” probes have ruled marks so the tech can measure how far in the duct it is. The bright blue backlight provides added visibility in dark areas. In addition, no calibration is required. With calibration data stored on the sensors, in case of loss, the sensors can be replaced without recalibration.

The SDP2 uses the same rugged ABS plastic case found on most other Fieldpiece standalone instruments surrounded by a familiar rubber boot. The ergonomic shape makes it simple to hold and with the included rubber clips the probe can be attached to the side of the meter for easy one-hand testing.

The SDP2 is priced competitively at $279.00 (suggested trade) and can be found at Fieldpiece distributors.