Key facts
- Brand
- EXTECH
- Model
- HD500
- Documents
- 5
- Languages
- ZH · EN
- Last added
- 2026-10-06
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Extech HD500 Heavy Duty Psychrometer User Manual
This user manual explains how to operate the Extech HD500 Heavy Duty Psychrometer, which measures air temperature, relative humidity, dew point, wet bulb, and surface temperature via its built-in IR thermometer. It includes instructions for basic measurements, data hold, min-max recording, auto power-off, and USB data transfer. Safety warnings for laser use are included.
The device features a triple digital LCD display, type K thermocouple input, USB interface, and backlight. Specifications cover temperature ranges, accuracy, and emissivity settings. Calibration and repair services are available through Extech’s customer support.
EXTECH HD500 specifications
| Display | Dual‑function LCD, 9999 pixels |
|---|---|
| Sample rate | 1 reading per second |
| Temperature sensor | Thermistor |
| Humidity sensor | Capacitive relative humidity |
| Infrared distance‑to‑spot ratio | 30:1 |
| Infrared spectral response | 6 µm to 14 µm |
| Infrared emissivity setting | 0.95 |
| Operating temperature range | 32 °F to 122 °F (0 °C to 50 °C) |
| Relative humidity range | up to 80 % |
| Dimensions | 10.1 × 3.0 × 2 in (257 × 76 × 53 mm) |
| Weight | 12.5 oz (355 g) |
All EXTECH HD500 documents by type
Day-to-day operation, settings and troubleshooting. Start here if the product is already set up.
Questions answered in these manuals
How do I switch between temperature, wet‑bulb and dew‑point displays?
Press the WB/DP button to toggle among air temperature, wet‑bulb temperature and dew‑point readings.
What does the HD500 measure?
It measures and displays air temperature, relative humidity, dew point, wet bulb, and surface temperature using the built-in IR thermometer.
From: Extech HD500 Heavy Duty Psychrometer + IR Thermometer User Guide
How do I take a non-contact IR surface temperature measurement?
Point the sensor toward the surface, then press and hold the IRT button; the laser pointer turns on to help aim.
From: Extech HD500 Heavy Duty Psychrometer + IR Thermometer User Guide
How do I switch between air temperature, wet bulb, and dew point readings?
Press the WB/DP button to toggle between Air, WB or DP.
What is the IR distance to spot ratio?
The meter’s field of view ratio is 30:1, meaning that if the meter is 30 inches (cm) from the target, the diameter (spot) of the object under test must be at least 1 inch (cm).
How do I disable the auto power off feature?
Hold the IRT button and then press the Power button to turn on; release the IRT button when 'disAPO' appears.
From: Extech HD500 Heavy Duty Psychrometer + IR Thermometer User Guide