testo 420 - Differential pressure measuring instrument

Order-Nr.  0560 0420

£ 755.00
incl. VAT £ 906.00
Delivery time: 3 – 5 working days
  • Differential pressure measurement, e.g. to check filters in air conditioning and ventilation systems

  • Calculate flow velocity and volume flow using a Pitot tube

  • Handy instrument featuring a large display and user-friendly menu guidance

  • Save measurement data for analysis and documentation

Use the testo 420 differential pressure measuring instrument to carry out simple, efficient tests on filters. You can also use the measuring instrument in conjunction with a Pitot tube to measure flow velocity and volume flow really easily in ventilation ducts.


Product Description

The testo 420 differential pressure measuring instrument is suitable for accurate differential pressure measurement up to 120 Pa, e.g. when checking filters in HVAC systems. Flow velocity and volume flow are calculated by the testo 420. The measuring instrument can also be used for absolute pressure measurement.

Differential pressure measuring instrument with practical functions

You can use a Pitot tube and compatible connection hoses (both optional) to measure the flow velocity and volume flow in ventilation ducts. Timed and multi-point mean calculation, as well as the combination of the two, along with simple input of the duct geometry provide you with support for measurements in ducts.

The automatic zeroing ensures higher accuracy for low pressures. All measuring values are easy to read on the large display which has an illumination function.

Documenting the measurement data

Measurement data can be stored in the differential pressure measuring instrument for analyses and documentation. It's easy to manage the measurement data on the PC without any additional software, via the plug & play function.

Delivery Scope

testo 420 differential pressure measuring instrument including batteries and calibration protocol.

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Technical Data

Differential Pressure - Piezoresistive

Measuring range

-120 to +120 Pa

+0.1 to +14 m/s


±2 % of mv + 0.5 Pa at +22 °C, 1013 hPa


0.001 Pa

0.01 m/s

Reaction time

1 s (t₉₀)

Absolute Pressure

Measuring range

700 to 1100 hPa


±3 hPa


0.1 hPa

Reaction time

1 s

General technical data


150 x 85 x 35 mm

Operating temperature

-5 to +50 °C


EU-guideline 2014/30/EU

Battery type

Alkali manganese, mignon, type AA

Battery life

40 h

Display size


Display function

Dot matrix

Display ligthing

with illumination




2 GB (internal)

Storage temperature

-20 to +60 °C


Additional accessories and Spare parts

£ 40.00
incl. VAT  £ 48.00
£ 45.00
incl. VAT  £ 54.00
£ 145.00
incl. VAT  £ 174.00
£ 399.00
incl. VAT  £ 478.80
£ 135.00
incl. VAT  £ 162.00

£ 755.00
incl. VAT £ 906.00
Delivery time: 3 – 5 working days