Testo 420 Specifications

testo 420 Flow hood

Lightweight, tough and accurate.

Weighs less than 6.2 lbs. (2.9 kg.)

Flow straightener for more precise measurement at

turbulent outlets

Large, tiltable, backlit display (removable)

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CFM

fpm

°F

App integration via Bluetooth for fast and easy monitoring

and reporting on site

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.

%RH

Pa

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.

www.testo.com/flowhood

testo 420

Technical data

testo 420 set

testo 420 flow hood base, 24" x 24" flow
hood, USB cable, batteries, soft case
w/ telescoping handle and wheels, NIST
Certificate

Part no. 400563 4200

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General technical data

Operating temperature 23 to 140 °F (-5 to +60 °C)

Storage temperature -4 to 140 °F (-20 to +60 °C)

Weight

Standard hood

Battery type Type AA

Battery life 30 h

Display Dot matrix with illumination

Memory 2 GB internal

Interface Micro USB

Warranty 2 years

6.3 lbs. (2.9 kg)

24" x 24" (610 x 610 mm)

Sensor types

Volume flow Temperature

Measuring range 50 to 2120 CFM

Accuracy

±1 digit

Resolution .5 CFM 0.1 °

±3 % of m.v.

-4 to 158 °F /

(-20 to +70 °C)

±0.9 °F (32 to 158 °F) /

±0.5 °C (0 to +70 °C)

Humidity sensor

0 to 100 %RH

±1.8 %RH

0.1 %RH

Dierential pressure

0 to 5" H2O /

(0 to 120 Pa)

±2 % of m.v.

0.001 Pa

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.

testo 420

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Accessories

Flow hood 12" x 48" (305 x 1220 mm)

Flow hood 24" x 48" (610 x 1220 mm)

Tripod, extendable to 13' (4m)

Connection hose; silicone; length 16.4' (5m); max. load 700 hPa (mbar)

Connection hose silicone-free for differential pressure measurement, length 16.4' (5m), load up to maximum 700 hPa, (mbar)

NIST Flow Hood Certification

Part no.

0554 4200Flow hood 14" x 14" (360 x 360 mm)

0554 4201

0554 4202

0554 4209

0554 0440

0554 0453

400520 4403

Probes

Probe type

Pitot tube, 19.6"(500 mm) long,

Ø .27" (7 mm), stainless steel, for

measuring flow velocity*

Pitot tube, 13.8" (350 mm) long,

Ø .27" (7 mm), stainless steel, for

measuring flow velocity*

Pitot tube, 39.4" (1000 mm) long,
Ø .27" (7 mm), stainless steel, for

measuring flow velocity*

*Connection hose required (order no. 0554 0440) or (order no. 0554 0453)

Dimensions

Probe shaft/probe shaft tip

19.6"
(500 mm)

13.8"
(350 mm)

39.4"
(1000 mm)

Ø .27"
(7 mm)

Ø .27"
(7 mm)

Ø .27"
(7 mm)

Measuring range

Measuring range: 198 to 19,680 ft/min

Operating temperature: 32 to 1,112 °F
(0 to 600 °C)
Pitot tube factor: 1.0

Measuring range: 198 to 19,680 ft/min

Operating temperature: 32 to 1,112 °F
(0 to 600 °C)
Pitot tube factor: 1.0

Measuring range: 198 to 19,680 ft/min

Operating temperature: 32 to 1,112 °F
(0 to 600 °C)
Pitot tube factor: 1.0

Part no.

0635 2045

0635 2145

0635 2345

Accurate even on critical applications

We measure it.testo 420

D.O.V1

Removable instrument allows Pitot tube measurements in ducts
(Pitot tube optional)

www.testo.com/flowhood

Subject to change without notice.