225-5230 & 225-5231 Assmann Psychrometer

The Model 225-5230 Assmann Psychrometer utilizes two precision mercury thermometers with 3-point calibrations. A calibration certificate gives the correction required at each point. Corrected accuracy is better than ± 0.1°C. The double-tube thermometers are protected by a chrome-plated brass case. The thermometer bulbs are guarded by double-walled radiation shields thermally isolated from the main housing by a plastic bushing. Aspiration of the bulbs is accomplished by a spring-wound fan which will provide eight minutes of aspiration per winding.

Two models are available, the 225-5230 measures over a range of -30° to +50°C and the 225-5231 has a range of -20° to +130°F. Each instrument is supplied with a wind shield, a mounting support, a syringe to moisten the wet-bulb wick, extra wicks, psychrometric tables, and a carrying case.


  • Range:
    • 225-5230: -30° to +50°C (0.2° graduations)
    • 225-5231: -20° to +130°F (0.5° graduations)
  • Accuracy: ± 0.1°C with corrections provided
  • Size: 4" dia x 16" L (100 mm x 405 mm)
  • Weight/shipping: 3 lbs/10 lbs (1.4 kg/4.5 kg)

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Available Options

* 225-5230 & 225-5231 Assmann Psychrometer:


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