Testo 420 Volume Flow Hood
The Testo 420 Volume Flow Hood helps HVAC professionals measure air volume quickly and accurately. Its lightweight design makes it easy to carry between locations. As a result, users can complete air balancing and ventilation checks with less effort.
Built for large air inlets and outlets, this instrument supports efficient airflow measurement in many environments. It is suitable for offices, industrial facilities and cleanrooms where indoor air quality is important. In addition, the large measuring hood helps capture airflow data across a wide operating range.
Designed for Accurate Airflow Measurement
A built-in flow straightener helps reduce measurement errors that can occur at swirl outlets. This improves consistency and helps users obtain dependable results. Furthermore, the measuring instrument can be tilted and removed for easier reading and handling.
The Testo 420 Volume Flow Hood combines airflow measurement with temperature, humidity and pressure monitoring capabilities. This allows technicians to gather more information during a single visit. Consequently, reporting and system assessment become more efficient.
Mobile Connectivity and Practical Handling
Bluetooth connectivity allows communication with compatible mobile devices through the free Testo app. Users can view readings, manage data and complete reports directly from site. Meanwhile, the bright dot matrix display provides clear visibility during daily use.
With a robust design and long battery life, the Testo 420 Volume Flow Hood is well suited to regular field work. Two different set types are available to suit different application requirements. A two-year warranty provides additional confidence for professional users.
Key Features
- Lightweight construction weighing less than 2.9 kg
- Designed for large air inlets and outlets
- Flow straightener reduces measurement errors
- Ergonomic handles improve manoeuvrability
- Removable measuring instrument
- Tiltable display position for easier viewing
- Bluetooth communication with mobile devices
- Compatible with iOS and Android app control
- Supports on-site report completion
- Bright illuminated dot matrix display
- Suitable for office, industrial and cleanroom environments
- Carry case with trolley included
- Efficient airflow balancing and verification
- Designed for indoor air quality assessments
- Long operating time between battery changes
- Available in two different set configurations
Technical Specifications
| Manufacturer | Testo |
| Manufacturer part code | 420 |
| Volume flow measuring range | 40 to 4000 m³/h |
| Volume flow resolution | 1 m³/h |
| Volume flow accuracy | ±3% of measured value +12 m³/h at +22°C and 1013 hPa |
| NTC temperature measuring range | -20°C to +70°C |
| NTC operating range | -20°C to +60°C |
| NTC resolution | 0.1°C |
| NTC accuracy | ±0.5°C from 0°C to +70°C and ±0.8°C from -20°C to 0°C |
| Humidity measuring range | 0 to 100% RH |
| Humidity resolution | 0.1% RH |
| Humidity accuracy | ±1.8% RH +3% of measured value at +25°C |
| Differential pressure range | -120 to +120 Pa |
| Differential pressure resolution | 0.001 Pa |
| Differential pressure accuracy | ±2% of measured value +0.05 Pa at +22°C and 1013 hPa |
| Absolute pressure range | +700 to +1100 hPa |
| Absolute pressure resolution | 0.1 hPa |
| Absolute pressure accuracy | ±3 hPa |
| Operating temperature | -5°C to +50°C |
| Storage temperature | -20°C to +60°C |
| Display | Dot matrix display with illumination |
| Memory | 2 GB internal memory approximately 18,000 measurements |
| Interface | Micro USB |
| Data transmission | Bluetooth |
| Compatibility | iOS 12.0 or newer and Android 6.0 or newer |
| Standard hood size | 610 x 610 mm |
| Weight | 2.9 kg |
| Battery type | Alkaline manganese Type AA batteries |
| Battery life | Up to 40 hours without illumination, Bluetooth off |
| Housing material | ABS measuring instrument housing |
| Hood material | Nylon |
| Warranty | 2 Years |
Comparison Table
| Sensor Type | Measuring Range | Accuracy | Resolution |
| Volume Flow | 50 to 4000 m³/h | ±3% of measured value +12 m³/h at +22°C, 1013 hPa | 1 m³/h |
| NTC Temperature | -20°C to +60°C | ±0.5°C from 0°C to +60°C and ±0.8°C from -20°C to 0°C | 0.1°C |
| Capacitive Humidity | 0 to 100% RH | ±1.8% RH +3% of measured value at +25°C | 0.1% RH |
| Differential Pressure | -120 to +120 Pa | ±2% of measured value +0.5 Pa at +22°C, 1013 hPa | 0.001 Pa |
| Absolute Pressure | +700 to +1100 hPa | ±3 hPa | 0.1 hPa |
Document Downloads
What’s Included
- Testo 420 Volume Flow Hood
- 610 x 610 mm measuring hood
- Tension rods
- USB cable
- Batteries
- Carry case with trolley
Meta Description
Testo 420 Volume Flow Hood with Bluetooth connectivity, flow straightener, 4000 m³/h range and lightweight 2.9 kg design.