Model-485B

Supported Applications

The Dwyer Model 485B is a handheld thermo-hygrometer designed for humidity, temperature, wet bulb, and dew point temperature detection in clean air. The instrument measures the percentage of relative humidity and temperature in °F or °C, with derived values displayed on the LCD.

Operating Conditions & Performance

The Model 485B operates within a process temperature range of -20 to 140°F (-28 to 60°C) for measurement and an ambient operating temperature of 5 to 125°F (-15 to 51°C). Relative humidity is measured from 0 to 100% (non-condensing).

• Relative Humidity Accuracy: ±2% FS over 10 to 90% @ 77°F (25°C)
• Temperature Accuracy: ±0.9°F @ 77°F (±0.5°C @ 25°C)
• Resolution: 0.1%, 0.1 °F/°C
• Display: 4.5 digit LCD with backlighting

The unit features a probe insertion length of 8" (203 mm) and weighs 16 oz (454 g). It is powered by an included 9 V alkaline battery, which includes a low-battery indicator on the display.

Configuration Options

The Model 485B-1 variant supports interchangeable probes within the Dwyer family without recalibration. The series offers specific functional capabilities for data logging and reading stability:

• Data Storage: Non-volatile memory stores up to 99 readings.
• Hold Function: Freezes current temperature and relative humidity readings on display.
• Dual Units: Displays measurements in imperial or metric units (°F/°C).

The instrument carries CE approval. Accessories available for the series include a protective magnetic rubber boot, hard carrying case, and various probe types including hot wire thermo-anemometer probes and vane thermo-anemometer probes.

Key Product Differences

The Model 485B is distinguished from other models in the family (such as the 471B-1 and 473B-1) by its specific focus on relative humidity measurement alongside temperature. While the 471B-1 utilizes a hot wire thermo-anemometer probe for air velocity, volumetric flow, and temperature, and the 473B-1 uses a vane thermo-anemometer probe for similar parameters, the Model 485B employs a dedicated thermo-hygrometer probe. The Model 485B does not measure air velocity or volumetric air flow.

Calibration options such as Certificate of Calibration (-COC), Factory Calibration (-FC), and NIST traceable calibration certificates are documented for the broader family but apply specifically to the 473B model; these specific option codes are not listed for the Model 485B in the provided documentation.