Testo 420 - Volume flow hood
Volume flow hood, with body, 610 x 610 mm flow hood, 5 x tension rods, USB cable, batteries and trolley
Part number: 0563 4200
The new volume flow hood testo 420 is the light, precise and convenient solution for regulating volume flows at larger air intakes and outlets. At swirl outlets in particular, the flow straightener significantly reduces the usual measurement errors. This allows users to fulfil hygienic Indoor Air Quality guidelines and stipulations in ventilation and air conditioning systems quickly and precisely, e.g. in industry, office rooms or in cleanrooms.
Handling is especially easy with a uniquely low weight of less than 2.9 kg and ergonomic handles. The measuring instrument can be tilted and removed for more comfortable readout of the measurement values. In addition to this, mobile devices can be used via Bluetooth App integration as a second display and remote control. This makes the use of a tripod for high ceilings especially secure and comfortable. Users can furthermore use the App to finalise and send the measurement report directly on site. The testo 420 App is completely free and is available for iOS from the App Store and Android via Google Play.
Strengths:
- Flow straightener for more precise measurement at swirl outlets
- Removable and tiltable measuring instrument with a large display
- App integration via Bluetooth for fast and easy monitoring and reporting on site

Despite it's size, the testo 420 is very light and easy to handle
Sensor types
| |
Volume flow |
NTC |
Capacitive humidity sensor |
Differential pressure sensor |
| Measuring range |
40 to 4000 m³/h |
-20 to +70 °C |
0 to 100 %RH |
0 to 120 Pa |
| Accuracy ±1 digit |
±3 % of m.v. +12 m³/h at +22 °C, 1013 hPa (85 to 3500 m³/h) |
±0.5 °C (0 to +70 °C) ±0.8 °C (-20 to 0 °C) |
±1.8 %RH +3 % of m.v. at +25 °C (5 to 80 %RH) |
±2 % of m.v. +0.05 Pa |
| Resolution |
1 m³/h |
0.1 °C |
0.1 %RH |
0.001 Pa |
General technical data
|
| Operating temperature |
-5 to +60 °C |
| Storage temperature |
-20 to +60 °C |
| Weight |
2.9 kg |
| Standard hood |
610 x 610 mm |
| Battery type |
Alkali manganese, mignon, Type AA |
| Battery life |
30 hrs |
| Display |
Dot matrix with illumination |
| Memory |
2 GB internal |
| Interface |
Micro USB |
| Warranty |
2 years |