Key facts
- Brand
- EXTECH
- Model
- HD300
- Industry
- Industrial
- Documents
- 3
- Languages
- ZH · EN
- Last added
- 2026-09-30
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Extech HD300 CFM/CMM Thermal Anemometer User Guide
The Extech HD300 is a handheld CFM/CMM thermal anemometer that measures air speed, airflow, ambient temperature and remote surface temperature using a built‑in non‑contact infrared sensor and laser indicator. It offers eight memory locations for duct area values, stores up to twenty average readings, and provides data hold, max/min/average functions, and an automatic shutdown feature.
The guide explains operation modes (velocity, flow, area), sensor setup, battery replacement, USB PC communication, infrared measurement theory, emissivity tables, conversion formulas, and detailed specifications such as measurement ranges, accuracy, and environmental limits. This manual is written in Chinese.
EXTECH HD300 specifications
| Display | Dual‑function LCD, 9999 pixels |
|---|---|
| Air velocity range | 0.40 – 30.00 m/s |
| Air velocity accuracy | ± (3 % + 0.20 m/s) |
| Temperature range (probe) | 14 – 140 °F (‑10 – 60 °C) |
| Battery | 9 V rechargeable |
| Automatic shutdown | 15 min idle (disableable) |
| PC interface | USB communication via random cable |
All EXTECH HD300 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 replace the battery?
Open the rear battery compartment, insert a new 9 V battery, and close the cover.
How can I disable the automatic shutdown feature?
Turn the instrument off, hold the IRT button while powering on, release the button when the prompt appears; the device will stay on until manually turned off.
What is the distance to spot ratio for the IR thermometer?
The device has a 30:1 distance to spot ratio.
From: Extech HD300 Heavy Duty CFM-CMM Thermo-Anemometer User Guide
How many memory locations are available for storing area values?
There are eight (8) memory locations for fast and easy recall of duct AREA values.
From: Extech HD300 Heavy Duty CFM-CMM Thermo-Anemometer User Guide
What is the maximum temperature this infrared thermometer can measure?
The built-in infrared thermometer measures non-contact surface temperatures up to 932°F (500°C).
From: EXTECH HD300 CFM/CMM Thermo-Anemometer with IR Temperature Product Datasheet
What are the physical dimensions of this instrument?
The product measures 8x3x1.9 inches, or 203x75x50mm.
From: EXTECH HD300 CFM/CMM Thermo-Anemometer with IR Temperature Product Datasheet