6-in-1 In-Duct Digital Psychrometer calculates enthalpy; determines system efficiency

April 22, 2015
The new 6-in-1 In-Duct Digital Psychrometer with Enthalpy (EP8711P) from General Tools & Instruments (General) is ideal for HVACR technicians.

The new 6-in-1 In-Duct Digital Psychrometer with Enthalpy (EP8711P) from General Tools & Instruments (General) is designed for HVACR technicians. It offers the ability to measure or calculate six parameters using a single instrument. It is designed for in-duct measurements upstream and downstream of the evaporator unit to determine an HVACR system's efficiency. By calculating enthalpy, the device also allows a technician to assess a system's efficiency before and after charging with a refrigerant.

The EP8711P can measure/calculate the following parameters:

  • Ambient Temperature
  • Relative Humidity (RH)
  • Dew Point (DP)
  • Wet Bulb Temperature (WBT)
  • Absolute Humidity (Mixing Ratio)
  • Enthalpy

The instrument's integral probe is designed for use inside ductwork in order to better measure conditions and diagnose system performance issues. The 6-inch sensor-tipped probe has linear insertion markings and an adjustable rubber bushing. The unit also features a 4-digit, 1.5 in. (38mm) LCD display. A protective probe cap and a belt clip make the EP8711P ultra-portable and convenient on the job. The swiveling ability of the probe and display makes the instrument very versatile, increasing positioning options to facilitate optimal viewing of readings. All parameters (except RH) can be displayed in Imperial or metric units.

The EP8711P offers the following ranges and accuracies:

  • Ambient Temperature: -4° to 158°F (-20° to 70°C)
  • Ambient Temperature Accuracy: +/-0.9°F (0.5°C) typical
  • RH Range: 0 to 100%
  • RH Range Accuracy: +/-3% typical
  • Dew Point Temperature Range: -76o to 158oF (-60o to 70oC)
  • Wet Bulb Temperature Range: -49o to 158oF (-45o to 70oC)
  • Absolute Humidity Range: 0 to 999 GPP (0 to 280g/kg)
  • Enthalpy Range: -8 to 318 Btu/lb. (-19 to 740kJ/kg)