TESTO 420 User manual

testo 420 · Flow Hood
Instruction manual

2

1 Contents
3
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1Contents
1Contents ..................................................................................3
2Safety and the environment .....................................................5
2.1. About this document ............................................................ 5
2.2. Ensure safety......................................................................... 6
2.3. Protecting the environment.................................................. 6
3Specifications...........................................................................6
4Technical data..........................................................................7
5Product description................................................................11
5.1. Overview .............................................................................11
5.1.1. Measurement setup .................................................................................................. 11
5.1.2. Overview of testo 420 ............................................................................................... 12
6First steps ..............................................................................14
7Using the product...................................................................16
7.1. Switching Bluetooth® on and off ........................................ 16
7.2. Settings for the measurement ............................................ 17
7.2.1. Damping (Gliding Average) ........................................................................................ 17
7.2.2. Hood Calibration........................................................................................................ 17
7.2.3. Zeroing Interval (Automatic Zeroing) ......................................................................... 17
7.3. Volume flow measurement setup.......................................18
7.4. Measuring ...........................................................................20
7.4.1. Volume flow measurement ....................................................................................... 20
7.4.2. Pitot tube measurement............................................................................................ 21
7.4.3. Differential pressure measurement........................................................................... 21
7.5. Saving .................................................................................. 22
7.6. Transferring measurement data to the PC ......................... 23
8Maintaining the product.........................................................23
8.1. Cleaning the instrument .....................................................23
9Tips and assistance.................................................................24
9.1. Questions and answers .......................................................24

1 Contents
4
9.2. Accessories and spare parts................................................ 24
10 Authorizations....................................................................... 26
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2 Safety and the environment
5
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2Safety and the environment
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2.1. About this document
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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.
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Symbols and writing standards
Representation
Explanation
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.
Menu
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

3 Specifications
6
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2.2. Ensure safety
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> Do not operate the instrument if there are signs of damage at
the housing, mains unit or feed lines.
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> Do not perform contact measurements on non-insulated, live
parts.
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> Do not store the product together with solvents. Do not use any
desiccants.
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> 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.
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> Dangers may also arise from the systems being measured or
the measuring environment: Note the safety regulations valid in
your area when performing the measurements.
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2.3. Protecting the environment
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> Dispose of faulty rechargeable batteries/spent batteries in
accordance with the valid legal specifications.
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> 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.
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3Specifications
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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.
The testo 420 can be connected to the additional testo Smart App
(Android/iOS) or the testo 400 via Bluetooth. This allows the
readings to be conveniently displayed on a tablet/smartphone or
the testo 400. Moreover, a measurement can be configured,
started, stopped and saved via the app/the testo 400.

4 Technical data
7
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4Technical data
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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 re-sale, export, import etc. in particular in countries without
wireless permits, is his responsibility.
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Feature
Values
Measurement
parameters
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 / mmH2O / inH2O
Measuring cycle
1/sec
Interfaces
Probe interface Mini DIN
Micro USB
Measuring ranges
Temperature: -20 to +60 °C / -4 to 140 °F
Humidity: 0 to 100% RH (Not for condensing
atmospheres. For continuous application in
high humidity (> 80 %RH at 30 °C for > 12
h, > 60 %RH at > 30 °C for > 12 h), contact
us via www.testo.com.)
Wet bulb temperature: -20 to +60 WB°C
Dew point: -76 to +60 td°C
Flow velocity: 0 to 14 m/s /
0 to 2750 ft/min
Volume flow: 50 to 4000 m³/h /
30 to 2350 cfm / 11 to 1100 l/s
Pressure (absolute pressure):
700 to 1100 hPa
Pressure (differential pressure): -
120 to +120 Pa

4 Technical data
8
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
Temperature: ±0.5 °C (0 to +60 °C) / ±0.8 °C
(-20 to 0 °C)
Humidity: ±1.8% RH +3% of m.v. at +25 °C
(5 to 80% RH)
±0,03 %RH/K (at 0 … 60 °C)
±1 %RH hysteresis
±1 %RH/year drift
Flow velocity: no accuracy specification since
calculated variable
Volume flow 1: ±3% of m.v. +12 m³/h at
+22 °C, 1013 hPa (85 to 3500 m³/h)
±3% of m.v. +7 cfm at +72 °F, 405 inH₂O (50
to 2,060 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
Minimum outlet size:
335 x 335 mm.
For smaller outlet sizes, the accuracy
specifications may vary.
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

4 Technical data
9
Feature
Values
Please ensure that the volume flow
hood is situated at the minimum
distance from the floor.
Incoming air (air flows from the outlet
into the room): 1 x height of the flow
hood.
Outgoing air (air flows from the room
into the duct): 0.5 x height of the flow
hood.
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

4 Technical data
10
Feature
Values
Housing /
measurement setup
Measuring instrument housing material: ABS
Body material: PP
Standard hood material: Nylon
Measuring instrument dimensions:
150x85x35 mm
Body dimensions: 510x456x148 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)
Display
Type: Dot matrix
Dimensions: 3.5 inches
Directives,
standards and tests
EU guideline: 2014/30/EU

5 Product description
11
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5Product description
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5.1. Overview
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5.1.1. 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

5 Product description
12
5.1.2. 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
Bluetooth
/ /
Measuring mode:
Pressure measurement, Pitot tube, volume
flow (air pressure from above into the hood /
suction outlet)
Actual
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.

5 Product description
13
Icon
Meaning
Standard
Standard volumetric flow:
The standard settings for temperature and
barometric pressure (21 °C / 1013 hPa in
accordance with the standard conditions of
the NIST, National Institute of Standards and
Technology) are used to calculate the
volume flow.
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
instruction manual or you should ask
your supplier.
Control keys
Key
Function
Menu
[►, ■]
Holds / starts / stops a measurement
[ESC]
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)

6 First steps
14
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6First steps
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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.
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
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
--

6 First steps
15
1. Menu Level
2. Menu Level
3. Menu Level
Continous
Measurement2
--
Continous/Punctual
measurement (nur für
Staurohr)
measuring duration3
Memory
New Folder
--
T420 folder
--
Display
Volume Flow
on/off
Diff.Pressure
on/off
Temperature
on/off
Velocity
on/off
Humidity
on/off
Abs.Pressure
on/off
Device Settings
Language
English/German/Itali
an/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
Reset Device
--
--
2
Maximum of 15 minutes, measuring cycle 1 second
3
Maximum of 25 points and 1 minute per point.

7 Using the product
16
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7Using the product
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7.1. Switching Bluetooth® on and off
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To establish a connection via Bluetooth, you need the
testo 400 (App version 14.31 or later) or a
tablet/smartphone with the testo Smart App already
installed on it.
The app is available for iOS devices in the App Store or for
Android devices in the Play Store.
Information about compatibility can be found in the
relevant App Store.
Measurements can be configured and carried out using
the testo 400 or the app and saved in the testo 420
instrument memory or directly on the testo 400 or the testo
Smart App. During Bluetooth connection to your testo
400/mobile device, the measuring mode and memory
function are not available on the testo 420.
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 -> Instrument settings -> Bluetooth, press ►and
▲/▼ to select -> On. 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.

7 Using the product
17
Display
Explanation
flashes
There is no Bluetooth connection, or a
potential connection is being searched for.
is permanently
displayed
There is a Bluetooth connection.
is not displayed
Bluetooth is disabled.
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7.2. Settings for the measurement
The sensor must not be exposed to volatile chemicals
such as solvents (e.g. ketene, ethanol, isopropyl alcohol,
toluene) or organic compounds, especially in high
concentrations and corresponding gases, over a
prolonged period of time.
7.2.1. Damping (Gliding Average)
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.
7.2.2. Hood Calibration
This input is provided for the filing of calibration data by the relevant
calibration laboratory. The flow hood-specific adjustment data can
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.
7.2.3. 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.
- The zeroing interval can be set between 1-20 seconds.

7 Using the product
18
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7.3. Volume flow measurement setup
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Standard hood
(610x610 mm, scope of delivery; 360x360 mm, accessories)
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. Screw together a short and long section of the support rods (4x)
at the silver ends.
5. Push the support rods (4x) through the hood, along the
markings and into the funnel in the measurement base.
6. Push the support rods (4x) on the top of the hood into the
bracket
- The hood is installed.

7 Using the product
19
Large hood
(1220x610 mm, 1220x305 mm and 915x915 mm, 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.
5. Screw together a short and long section of the support rods (4x)
at the silver ends.
6. Push the support rods (4x) through the hood, along the
markings and into the funnel in the measurement base.
7. Push the support rods (4x) on the top of the hood into the
bracket
- The hood is installed.

7 Using the product
20
Attaching the measuring instrument
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.
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7.4. Measuring
7.4.1. 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.