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Testo 420

Available for hire

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The Testo 420 is an easy to use high accuracy lightweight volume flow hood specifically designed for the HVAC market which includes use in clean rooms and systems employing the use of swirl diffusors. The standard assembly with the 610mm x 610mm hood weighs just 2.9kg which makes the instrument ideal for use over extended periods, and it has been designed with the user in mind with ergonomic handles, adjustable display panel, a long battery life and a range of accessories.

Optional accessories include x3 different sized hoods, an extendable tripod and pitot tubes when the 420 is used as a stand alone pressure device.

Product Features

  • Calibration options
  • Document downloads

Instrument product options

1. Select a model (1 available)

Model subtotal: £1,990.00
Total (excl VAT): £1,990.00
Continue to select accessories

2. Select accessories

3. Select a calibration (3 available)



  • Light weight, at only 2.9kg with the standard hood assembly its lighter than any other similar hood in the market.
  • Built in flow straightener specifically designed for use with outlets generating turbulent air patterns.
  • Easy to use Bluetooth mobile App which enable you to both receive and send messages to the instrument.
  • Ergonomic design with a tilting display for easy of viewing measurements and comfortable handles
  • Quick set-up with a meter display life of 30 hours.
  • Custom designed carry case for easy transportation.


Air volume range     40 to 4000 m3/h  (11.1 to  1111.1 l/s)

Air volume measurement units    m3/h, m3/min, cfm and l/s

Air volume accuracy     ±3 % of m.v. + 12 m3/h ± 1 digit

Differential pressure range      0 to 120 Pa

Differential pressure units     Pa, hPa, mbar, mmH2O and inH2O

Differential pressure accuracy      ± 2 % of m.v. + 0.05 Pa

Differential pressure resolution      0.0001 Pa




Testo 420 balometer data sheet

  • Technical Document
  • PDF file
  • 2 MB

Testo 420 quick start guide

  • Technical Document
  • PDF file
  • 1 MB

Testo 420 user manual

  • Technical Document
  • PDF file
  • 2 MB
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