Model-471B

Supported Applications

The Dwyer Model 471B is a dual function digital thermo-anemometer designed to measure air velocity, volumetric airflow, and temperature in clean, dry air. The instrument serves HVAC applications where simultaneous monitoring of flow conditions and thermal parameters is required.

Operating Conditions & Performance

The Model 471B operates within a process air velocity range of -20 to 212°F (-29 to 100°C) for the probe, with an ambient operating temperature of 5 to 125°F (-15 to 51°C). The measurement envelope covers:

• Air Velocity Range: 45 to 6000 FPM (0.23 to 30 m/s).
• Volumetric Air Flow Range: Up to 19,999 in selected flow units.
• Temperature Range: -40 to 212°F (-40 to 100°C).

Air velocity accuracy is specified as ±3% FS within a temperature range of 40 to 90°F (4 to 32°C). Temperature accuracy varies by range: ±0.5°F (±0.28°C) from 32 to 122°F (0 to 50°C), and ±1.5°F (±0.83°C) from -40 to 32°F (-40 to 0°C) & 122 to 212°F (50 to 100°C). The instrument features a resolution of 0.1% and 0.1°F/°C, displayed on a 4.5 digit LCD with backlight.

Configuration Options

The Model 471B is configured as a handheld unit powered by a user-replaceable 9 V alkaline battery (installed non-functional). The series includes the following configurable and fixed features:

• Housing & Probe: Extruded aluminum housing with an integral sliding sensor cover. Includes a stainless steel probe with insertion depth marks from 0 to 8 inches and 0 to 20 cm.
• Data Storage: Capable of storing up to 99 readings for later retrieval.
• Cable Management: Features a coiled cable that retracts to 28" (71 cm) and extends to 6 ft (183 cm).
• Approvals: CE marked.

The unit includes a low battery warning indicator. The probe side with the dot must face the flow for proper operation.

Key Product Differences

The Model 471B is part of a broader family that includes Models 473B-1 and 485B-1, which share compatible electronics but utilize different probe technologies. The Model 471B specifically employs a hot wire thermo-anemometer probe (AP1 type) for air velocity measurement.

Key distinctions within the family include:

• Model 473B-1: Uses a 100 mm vane thermo-anemometer probe; offers higher accuracy options and supports relative humidity measurements with specific probes.
• Model 485B-1: Designed as a thermo-hygrometer for measuring relative humidity (0 to 100% RH) and air temperature, without air velocity measurement capability.

All models in the series support interchangeable AP1, RP1, and VP1 probes which are automatically recognized by the handheld unit. The Model 471B-1 weighs 16 oz (454 g).