• Flow Hood Balometer

Flow Hood Balometer

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The new testo 420 flow hood is the light, precise and convenient solution for regulating volume flows at supplies and returns.

At turbulent outlets in particular, the flow straightener significantly improves measurement accuracy, saving you time and headaches for these difficult situations. Handling is especially easy with the low weight of less than 6.2 lbs. and ergonomic handles. The display can be tilted for more comfortable readout. In addition, Bluetooth will allow for connection to mobile devices, which can be used as a second display or remote control. This makes the use of a tripod (optional) for high ceilings especially easy. Furthermore, users can utilize the App to finalize and send measurement reports while still on site.


Features and specifications

Testo 420 Set
testo 420 flow hood base, 24" x 24" flow hood,
USB cable, batteries, soft case w/ telescoping
handle and wheels, NIST
Réf. 0563 4200
Transport case
Detachable Differential Pressure (t420) instrument allows Pitot tube measurements in ducts (Pitot tube optional) Detachable Differential Pressure instrument
Compatibility iOS 7.1 min. / Android 4.3 min.
 Bluetooth 4.0 min.
Operating temperature 23 to 140 °F / -5 ... +50 °C
Storage temperature -4 to 140 °F / -20 ... +60 °C
Weight 6.3 lbs. / 2.9 kg
Standard hood 24" x 24" / 610 x 610 mm
Battery type type AA
Battery life 40 h
Display Dot matrix with illumination
Memory 2 GB internal
Interface Micro USB
Warranty 2 years

Sensor types

  Volume flow Temperature Humidity sensor Humidity sensor
Measuring range 50 to 2120 CFM -4 to 158 °F /
(-20 to +70 °C)
0 to 100 %RH 0 to 5" H2O /
(0 to 120 Pa)
±1 digit
±3 % of m.v. ±0.9 °F (32 to 158 °F) /
±0.5 °C (0 to +70 °C)
±1.8 %RH ±2 % of m.v.
Resolution .5 CFM 0.1 °C 0.1 %RH 0.001 Pa



Functional principle of the flow straightener.

Flow straightener

Bluetooth App

Sturdy, wheeled tripod

Functional principle of the flow straightener. Flow straightener for significantly more precise measurements at turbulent outlets. Bluetooth App allows for hands free operation, displaying measurement data on mobile devices and finalizing the measurement report on site Sturdy, wheeled tripod (optional) with central fitting for safe measuring of high ceiling outlets