Testo 420 Operating Manual

testo 420 · Flow Hood

Instruction manual

2

1 Contents

1 Contents

1 Contents ................................................................................................... 3

2 Safety and the environment .................................................................... 4

2.1. About this document ........................................................................ 4

2.2. Ensure safety................................................................................... 5

2.3. Protecting the environment .............................................................. 5

3 Specifications .......................................................................................... 5

3.1. Use .................................................................................................. 6

3.2. Technical data ................................................................................. 6

3.2.1. Bluetooth module ................................................................................................ 6

3.2.2. General technical data ........................................................................................ 7

4 Product description ............................................................................... 10

4.1. Overview ....................................................................................... 10

4.1.1. Measurement setup ..........................................................................................10

4.1.2. Overview of testo 420 .......................................................................................11

5 First steps .............................................................................................. 12

6 Using the product .................................................................................. 14

6.1. Switching Bluetooth® on and off.................................................... 14

6.2. Settings for the measurement........................................................ 15

6.2.1. Damping (Gliding Average) ..............................................................................15

6.2.2. Hood Calibration ...............................................................................................15

6.2.3. Zeroing Interval (Automatic Zeroing) ................................................................16

6.3. Volume flow measurement setup .................................................. 16

6.4. Measuring ...................................................................................... 19

6.4.1. Volume flow measurement ...............................................................................19

6.4.2. Pitot tube measurement ....................................................................................19

6.4.3. Differential pressure measurement...................................................................19

6.5. Saving ........................................................................................... 20

6.6. Transferring measurement data to the PC .................................... 21

7 Maintaining the product ........................................................................ 22

7.1. Cleaning the instrument ................................................................. 22

8 Tips and assistance............................................................................... 22

8.1. Questions and answers ................................................................. 22

8.2. Accessories and spare parts ......................................................... 23

9 EC Declaration of Conformity ............................................................... 24

3

2 Safety and the environment

Representation

Explanation

Menu

2 Safety and the environment

2.1. About this document

Use

> Please read this documentation through carefully and

familiarize yourself with the product before putting it to use. Pay
particular attention to the safety instructions and warning advice
in order to prevent injuries and damage to the products.

> Keep this document to hand so that you can refer to it when

necessary.

> Hand this documentation on to any subsequent users of the

product.

Symbols and writing standards

Warning advice, risk level according to the
signal word:

Warning! Serious physical injury may occur.
Caution! Slight physical injury or damage to

the equipment may occur.
> Implement the specified precautionary

measures.

Note: Basic or further information.

1. ...

2. ...

Action: more steps, the sequence must be
followed.

> ... Action: a step or an optional step.

- ... Result of an action.

Elements of the instrument, the instrument
display or the program interface.

[OK]

Control keys of the instrument or buttons of
the program interface.

... | ... Functions/paths within a menu.

“...” Example entries

4

2.2. Ensure safety

> Do not operate the instrument if there are signs of damage at

the housing, mains unit or feed lines.

> Do not perform contact measurements on non-insulated, live

parts.

> Do not store the product together with solvents. Do not use any

desiccants.

> Carry out only the maintenance and repair work on this

instrument that is described in the documentation. Follow the
prescribed steps exactly. Use only original spare parts
from Testo.

> Dangers may also arise from the systems being measured or

the measuring environment: Note the safety regulations valid in

2.3. Protecting the environment

your area when performing the measurements.

> Dispose of faulty rechargeable batteries/spent batteries in

accordance with the valid legal specifications.

> At the end of its useful life, send the product to the separate

collection for electric and electronic devices (observe local
regulations) or return the product to Testo for disposal.

3 Specifications

3 Specifications

The testo 420 is used for volume flow measurements (main
application), Pitot tube measurements and pressure measurements
for air conditioning and ventilation systems. Thanks to its
interchangeable flow hoods, the testo 420 can be used for air inlets
and outlets of various sizes.

With the additional App (Android/iOS), the readings can be
conveniently displayed on a tablet or smartphone, and in addition a
measurement can be started, stopped and saved via the App.

5

3 Specifications

3.1. Use

3.2. Technical data

The use of the wireless module is subject to the regulations and
stipulations of the respective country of use, and the module may only
be used in countries for which a country certification has been granted.
The user and every owner has the obligation to adhere to these
regulations and prerequisites for use, and acknowledges that the re­sale, export, import etc. in particular in countries without wireless
permits, is his responsibility.

3.2.1. Bluetooth module

Feature Values

Bluetooth Range >20 m (free field)

Bluetooth type LSD Science & Technology Co., Ltd

L Series BLE module (08 May 2013) based
on TI CC254X chip

Qualified Design ID B016552

Bluetooth radio
class

Bluetooth company 10274

Class 3

Certification

Belgium (BE), Bulgaria (BG), Denmark (DK), Germany (DE),
Estonia (EE), Finland (FI), France (FR), Greece (GR), Ireland (IE),
Italy (IT), Croatia (HR), Latvia (LV), Lithuania (LT), Luxembourg
(LU), Malta (MT), Netherlands (NL), Austria (AT), Poland (PL),
Portugal (PT), Romania (RO), Sweden (SE), Slovakia (SK),
Slovenia (SI), Spain (ES), Czech Republic (CZ), Hungary (HU),
United Kingdom (GB), Republic of Cyprus (CY).

EFTA countries

Norway

Other countries

USA, Turkey, India and Hong Kong

6

Information from the FCC (Federal Communications Commission)
This instrument complies with part 15 of the FCC Rules. Its

commissioning is subject to the following two conditions: (1) This
instrument may not cause harmful interference and (2) this
instrument must be able to accept interference, even if this could
have undesired effects on the operation.

Changes
The FCC demands that the user be informed that any changes or

modifications to the instrument that are not explicitly approved by
Testo AG may void the user's right to use this instrument.

3.2.2. General technical data

Feature Values

Measurement
parameters

Measuring cycle 1/sec

Interfaces Probe interface Mini DIN

Measuring ranges Temperature: -20 to +60 °C / -4 to 140 °F

Temperature: °C / °F
Humidity: %RH / %rF / td°C / WB°C
Flow velocity : m/s / ft/min
Volume flow: m³/h / cfm / l/s
Pressure (absolute pressure): hPa / mbar / kPa
Pressure (differential pressure): Pa / hPa /

mbar / mmH

Micro USB

Humidity: 0 to 100% RH

Flow velocity: 0 to 14 m/s /
0 to 2750 ft/min

Volume flow: 40 to 4000 m³/h /
25 to 2300 cfm / 11 to 1100 l/s

Pressure (absolute pressure):
700 to 1100 hPa

Pressure (differential pressure): ­120 to +120 Pa

O / inH2O

2

3 Specifications

7

3 Specifications

since

Feature Values

Resolution Temperature: 0.1 °C / 0.1°F

Humidity: 0.1% RH
Flow velocity: 0.01 m/s
Volume flow: 1 m³/h / 1 cfm
Pressure (absolute pressure): 0.1 hPa /

0.1 mbar / 0.01 kPa
Pressure (differential pressure): 0.001 Pa /

0.00001 hPa / 0.00001 mbar / 0.0001 mm
H2O / 0.000001 inH2O

Accuracy
(nominal temperatur
e 22°C/71.6°F)

Temperature: ±0.5 °C (0 to +70 °C) / ±0.8 °C
(-20 to 0 °C)

Humidity: ±1.8% RH +3% of m.v. at +22 °C
(5 to 80% RH) (longer high humidity application
can result in a temporary sensor drift)

Flow velocity: no accuracy specification
calculated variable

Volume flow 1: ±3% of m.v. +12 m³/h at
+22 °C, 1013 hPa (85 to 3500 m³/h)

±3% +7 cfm (50 to 2,100 cfm)
Error absolute pressure compensation:

±0.04% of m.v. / hPa deviating from 1013 hPa

Pressure (absolute pressure): ± 3 hPa

Pressure (differential pressure): ±2% of m.v.
+ 0.5 Pa (at 22°C, 1013 hPa)

Error absolute pressure compensation:
±0.04% of m.v. / hPa deviating from 1013 hPa

1

All accuracy specifications apply under laboratory conditions or with necessary
compensation (correction factor) with the standard hood 610x610 mm. Minimum
outlet size of 360x360 mm.

8

3 Specifications

Feature Values

Temperature
coefficient

Humidity: ± 0.03% RH / K (deviating from
22°C, in the range 0 to 60 °C)

Volume flow: ± 0.02% of m.v. / K
(deviating from 22 °C, in the range 0 to 60 °C)

Pressure (absolute pressure): ± 0.02% of
m.v. / K (deviating from 22 °C, in the range
0 to 60 °C)

Pressure (differential pressure): ± 0.02% of
m.v. / K (deviating from 22 °C, in the range
0 to 60 °C)

Response time t90 Temperature: approx. 45 s

Humidity: approx. 15 s
Flow velocity: approx. 1 s
Volume flow: approx. 1 s
Pressure (absolute pressure): approx. 1 s
Pressure (differential pressure): approx. 1 s

Operating and
ambient conditions

Storage temperature: -20 to +60 °C / -4 to
140 °F

Operating temperature: -5 to +50 °C/+23 ­+122°F

Humidity: 0 to 100% RH
Pressure range: 800 to 1100 hPa

Housing /
measurement setup

Measuring instrument housing material: ABS
Body material: PP
Standard hood material: Nylon
Measuring instrument dimensions:

150x85x35 mm
Body dimensions: 490x970x610 mm
Dimensions of measurement setup with

standard hood: 610x970x610 mm
Weight of entire measurement setup

approx. 2900 g

Power supply 4 x 1.5 V rechargeable/non-rechargeable

batteries
Type AA / alkaline manganese, mignon
Battery lifetime: approx. 40h (eroing interval

10 seconds, display illumination off,
Bluetooth off)

9

4 Product description

Feature Values

Display Type: Dot matrix

Dimensions: 3.5 inches

Directives,
standards and tests

Warranty Duration: 2 years

EU guideline: 2014/30/EU

Warranty terms: see website
www.testo.com/warranty

4 Product description

4.1. Overview

4.1.1. Measurement setup

1 Volume flow hood (standard hood 610x610 mm)
2 Actuator for manual measurement
3 Measuring instrument testo 420
4 Measurement base with differential pressure cross
5 Integrated flow straightener

10

4.1.2. Overview of testo 420

1 Battery compartment, on rear of the instrument
2 Display
3 Control keys
4 Probe socket Mini-DIN (only for use on the measurement base)
5 Micro-USB port
6 Connection for pressure measurement

Instrument status icons:

Icon Meaning

Battery capacity

/ /

Actual

Standard

Bluetooth

Measuring mode:
Pressure measurement, Pitot tube, volume

flow (air pressure from above into the hood /
suction outlet)

Actual volume flow:
The current ambient conditions are used to

calculate the volume flow. The actual
barometric pressure is measured with the
internal sensor. In applications with volume
flow hood, the temperature is measured by
the integrated temperature/humidity sensor,
with Pitot tube measurement the actual
temperature needs to be input manually.

Standard volume flow:
The standard settings for temperature and

barometric pressure (21 °C / 1013 hPa) are
used to calculate the volume flow.

4 Product description

11

5 First steps

instruction manual or you should ask your

Icon Meaning

K-factor

Factor by which the current reading is
multiplied. Depends on which outlet
measurements are being taken at.

Pitot Tube factor

(P-factor)

The Pitot tube factor for Pitot tubes is
generally the same and must be entered:

• Pitot tubes from Testo: 1.00

• Pitot tubes from other manufacturers: the

Pitot tube factor can be found in the

supplier.

Control keys

Ke y Function

Menu

[►, ■]

[ESC]

[►, ▲, ▼,◄]

[ ]

5 First steps

Inserting batteries/rechargeable batteries

1. Open the battery compartment.

2. Insert the batteries or rechargeable batteries (scope of delivery
includes 4x 1.5V Type AA/ LR6).

3. Close the battery compartment.

When not in use for a long period of time, take the
batteries/rechargeable batteries out.

Holds / starts / stops a measurement

Switches to the previous view / to the
measurement view

Saves the measured values

Navigation within the menu

Confirms a selection

Switch instrument on/off (press and hold
down)

Switch illumination on/off (press briefly)

12

5 First steps

►, ▲, ▼,◄

measurement (nur für

Implementing settings

1. Press to access the menu.

2. Select the menu item you require using ►, ▲, ▼, ◄.

Key functions

Display Explanation

Change parameter, select unit

Confirm input

adjustable parameters

1. Menu Level 2. Menu Level 3. Menu Level

Application Flow Hood K-factor

Actual/Standard

Pitot tube Duct

Pitot tube factor

Pitot Temperature

Actual/Standard

Pressure only --

Measuring Program Single Measurment --

Continous
Measurement

2

Continous/Punctual

--

measuring duration

3

2

Maximum of 15 minutes

3

Maximum of 25 points and 1 minute per point.

13

Staurohr)

Memory New Folder --

T420 folder --

Display Volume Flow on/off

Diff.Pressure on/off

Temperature on/off

6 Using the product

Information about compatibility can be found in the relevant

1. Menu Level 2. Menu Level 3. Menu Level

Device Settings Language English/German/Italia

Reset Device -- --

Velocity on/off

Humidity on/off

Abs.Pressure on/off

n/French/Spanish

Backlight Auto Off On/Off

Auto Off On/Of

Bluetooth On/Off

Date&Time Date Format

Time Format

Set Date&Time

Gliding average 5 – 20 sec

Hood adjustment Supply Air

Exhaust Air

Zeroing int 1-20 sec

6 Using the product

6.1. Switching Bluetooth® on and off

In order to be able to establish a connection via Bluetooth,
you need a tablet or smartphone with the Testo App testo
420 already installed on it.

You can get the App for iOS instruments in the App Store
or for Android instruments in the Play Store.

App Store.

14

6 Using the product

Display

Explanation

Measurements can be performed and saved with App into
the instruments memory. Measuring mode and save
function on the instrument itself is not available during
Bluetooth communication is established with a mobile
device.

Switching on Bluetooth

1. Hold ▲ down for 3 seconds.

- Once the Bluetooth icon is shown on the display, Bluetooth is
switched on.

- If no connection is established, Bluetooth switches off after 10
mins.

or

1. Press -> Device Settings -> Bluetooth, ► and using ▲/▼

-> select Off. Confirm with .

- Once the Bluetooth icon is shown on the display,
Bluetooth is switched on.

- If no connection is established, Bluetooth switches off after 10
mins.

6.2. Settings for the measurement

6.2.1. Damping (Gliding Average)

6.2.2. Hood Calibration

15

flashes

is permanently

There is no Bluetooth connection, or a
potential connection is being searched for.

There is a Bluetooth connection.

displayed

is not displayed

Bluetooth is disabled.

If the readings fluctuate widely, it is advisable to damp the
readings. The time range for the damping can be set manually
between 5-20 seconds.

1. Press , then select Device settings and Gliding average.

- The damping can be set between 5-20 seconds.

This input is provided for the filing of calibration data by the relevant
calibration laboratory. The flow hood-specific adjustment data can

6 Using the product

be input manually for supply air and exhaust air and has a direct
effect on the measurement results. Input option of 0.001-9.999.

1. Press , then select Device settings and Hood adjustment.

- Calibration of the hood can be set for supply air and exhaust air.

6.2.3. Zeroing Interval (Automatic Zeroing)

The pressure sensor carries out automatic zeroing at regular
intervals. These intervals can be set via the automatic zeroing.

1. Press , then select Device settings and Zeroing int.

6.3. Volume flow measurement setup

- The zeroing interval can be set between 1-20 seconds.

Standard hood (610x610 mm, scope of delivery; 360x360, accessories)

16

6 Using the product

1. Pull the lower end of the hood over the measurement base.

2. Attach the hood at two corners using the snap fasteners.

3. Tighten the closure.

4. Push the support rods through the hood, along the markings
and into the funnel in the measurement base.

5. Push the support rods on the top of the hood into the brackets.

- The hood is installed.

Large hood (1220x610 and 1220x305, accessories)

1. Install the aluminium frame and stretch the fabric hood over the
framework, so that the elastic band lies in the recess of the
frame. Make sure that the elastic band fits correctly, especially
at the corners.

2. Pull the lower end of the hood over the measurement base.

3. Attach the hood at two corners using the snap fasteners.

4. Tighten the closure.

17

6 Using the product

5. Push the support rods through the hood, along the markings

6. Push the support rods on the top of the hood into the brackets.

- The hood is installed.

Attaching the measuring instrument

and into the funnel in the measurement base.

1. Push the testo 420 completely into the instrument holder, pay

attention to the catch on the right-hand and left-hand side in the
bracket.

18

6.4. Measuring

6.4.1. Volume flow measurement

✓ The volume flow hood is fitted.

1. Switch on the instrument.

2. In the instrument settings, set the application volume flow hood
and also the required measurement program:
Single measurement or Continuous measurement.

3. Press ►, ■ on the testo 420, or the trigger on the measurement
base to hold or start and stop the measurement.

4. Press to save the measurement data. Unsaved
measurement data is lost once you carry out the next
measurement.

- The target folder and file name are displayed, confirm with
to save the measurement data under this name and in the
selected folder.

6.4.2. Pitot tube measurement

1. Remove the testo 420 from the measurement base.

2. Connect the hoses to the testo 420 and to the Pitot tube.

3. Press -> Application -> Pitot tube and there set the duct
geometry, the Pitot tube factor and the temperature, and
choose between actual and standard.

4. Select the required measurement program.

5. Carry out the measurement.

6. Press to save the measurement data. Unsaved
measurement data is lost once you carry out the next
measurement.

- The target folder and file name are displayed, confirm with
to save the measurement data under this name and in the
selected folder.

6 Using the product

6.4.3. Differential pressure measurement

1. Remove the testo 420 from the measurement base.

2. Connect the hoses to the testo 420 at + and -.

3. Press -> Application -> Pressure only.

4. Carry out the measurement.

19

6 Using the product

5. Press to save the measurement data. Unsaved

measurement data is lost once you carry out the next
measurement.

- The target folder and file name are displayed, confirm with

to save the measurement data under this name and in the
selected folder.

6.5. Saving

A maximum of 99 measurements can be saved in one
folder.

> -> Memory ->

- The folder overview is shown on the display. Create a new

folder via New Folder.

Open folder

> Using the arrow keys, navigate to the required folder and press

.

- The selected folder is opened and the individual files are

displayed.

Delete folder

1. Using the arrow keys, navigate to the required folder and press

.

2. Select the menu item Delete Folder and confirm with .

- The folder that you want to delete is shown on the display.

3. Confirm once again with in order to delete the folder,

or cancel by pressing Esc.

20

Set as Logging Folder

This setting establishes which folder is to be specified as the
standard storage location for saving the measurements.

The folder which is set as the standard storage location is
marked in black.

1. Using the arrow keys, navigate to the required folder and press

.

2. Select the menu item Set as Logging Folder and confirm with

.

- The selected folder is set as the standard storage location.

- The stored location can be changed during the saving process.

6 Using the product

the total volume flow of all measurements can be displayed

Total Volume Flow

If data from single measurements is saved within a folder,

using this function.

1. Using the arrow keys, navigate to the required folder and press

.

2. Select the menu item Total Volume Flow and confirm with .

- The single measurements and the total volume flow are
displayed.

3. Press .

- The result of the total volume flow is saved.

6.6. Transferring measurement data to the PC

No Bluetooth connection is possible while there is a
connection to the PC. The existing Bluetooth connection is
aborted.

1. Connect the testo 420 to your PC using the USB cable.

- The testo 420 switches on automatically, a window appears on
the PC, select Open folder here. The folders and files saved on
your testo 420 are displayed. The files are available in the file
format *.txt.

21

8 Tips and assistance

Can not

available in Bluetooth

instrument is connected to a Tablet

7 Maintaining the product

7.1. Cleaning the instrument

Do not use any aggressive cleaning agents or solvents!
Mild household cleaning agents or soap suds may be used.

> If the housing of the instrument is dirty, clean it with a damp

8 Tips and assistance

8.1. Questions and answers

cloth.

Question Possible causes/solution

For selected parameters,
no values are shown on

No temperature/humidity probe is

connected, for instance.
the instrument display
(-----)

Warning message

turn on! when selecting

certain parameters in the
Display menu.

• This parameter is not available for
the application currently selected.

• Four parameters are already
displayed. Disable the display of
one parameter to enable another
one.

• [►, ■] on the

• Bluetooth connection is active, the

instrument does not
work.

• Warning message

Function not

or Smartphone via Bluetooth and
the App is active.

• Fully close the App or end the
Bluetooth connection.

mode.

22

8.2. Accessories and spare parts

free, for differential

Description Article no.

Flow hood 360x360 mm 0554 4200

Flow hood 305x1220 mm 0554 4201

Flow hood 610x1220 mm 0554 4202

Fabric cover for the hood 610x610 0400 4200

Aluminium frame for the hood 610x610 0440 4204

Tripod, extendable to 4 m 0554 4209

Connection hose, silicone, length 5 m,
maximum load capacity 700 hPa (mbar)

Connection hose, silicone­pressure measurement, length 5 m,
maximum load capacity 700 hPa (mbar)

Pitot tube, length 500 mm, Ø 7 mm, stainless
steel, for measuring flow velocity
(Connection hose required)

Pitot tube, length 350 mm, Ø 7 mm,
stainless steel, for measuring flow velocity
(Connection hose required)

Pitot tube, 1,000 mm long, stainless steel,
measures flow velocity
(Connection hose required)

Connection hose 0554 0453

Tension rod 0440 4201

8 Tips and assistance

0554 0440

0554 0453

0635 2045

0635 2145

0635 2345

For a complete list of all accessories and spare parts, please refer
to the product catalogues and brochures or visit our website
www.testo.com

If you have any questions, please contact your dealer or Testo
Customer Service. The contact details can be found on the back of
this document or on the Internet at www.testo.com/service-
contact..

23

9 EC Declaration of Conformity

9 EC Declaration of Conformity

24

0970 4200 en 01 V01.00