Digital Hygrometer

TDI’s Digital Hygrometer is a precision electronic instrument that measures relative humidity and temperature in desiccators and glove boxes. (A hygrometer is not required when the Nitro-Save® option is chosen).

Model: #715H for Clear Acrylic and #715HSD for Static Dissipative Acrylic

Range: Humidity – 10% to 99% RH
Range: Temperature – 50°C to 70°C (-58°F to 158°F)

Accuracy: Humidity – +/- 5%RH
Accuracy: Temperature – +/- 1°C (1.8°F)

Battery: AG10

Digital Hygrometer

Start Up

The unit will begin to function automatically once the battery insulating tape is pulled off.

Maximum Humidity & Temperature Recording

  1. The MAX/MIN humidity and temperature is recorded automatically.
  2. Press MAX/MIN button to read the MAX/MIN humidity and temperature since the last time the CLEAR button has been pressed.  Respective to MAX or MIN indicator will be displayed.
  3. Hold CLEAR button for 2 seconds to reset memory of MAX/MIN reading.

°C / °F Slider Switch

Selects between Celsius (°C) or Fahrenheit (°F) temperature unit display.

Battery Replacement

Slide open the built-in compartment and replace the exhausted battery with a new 1.5V AG10 battery according to the polarity shown.  The unit will resume working in a few seconds.


  • DO NOT subject the unit to water, AC power or extreme weather conditions. Operate the unit within -50°C to 50°C, 10% to 99%RH.
  • If the humidity area of the display shows “–%” it means the measured temperature is lower than the -50°C or higher than 60°C, or the measured humidity is lower than 10%. We do not recommend using the unit for use in the former cases with extreme high or low temperature. When the ambient conditions resume normal operation range, the humidity area of the display will show the correct humidity accordingly.
  • DO NOT intend to dismantle the unit’s internal components..
  • DO NOT insert any used battery or any other battery type except AG10. Likewise, dispose of used batteries properly with environmental care as they are harmful.

TDI desiccator cabinets require a continuous in-line nitrogen (N2) or clean dry air (CDA) source.  The N2/CDA goes in through the flowmeter to the plenum chamber.  The gas then flows evenly into and between the chambers via our Ultra Nitro-Flow system. Equally important, the excess N2/CDA automatically bleeds off via the bleeder valve at the bottom of the cabinet.  TDI desiccators do not require and are not compatible with desiccants or any other types of drying agents.