testo 330i - flue gas analyzer (with H₂-compensated CO measuring cell)

Order-Nr.  0632 3000 71

  • Paperless documentation and report generation on site via smartphone app

  • Operation independent of measuring location via smartphone app

  • No more probe slippage thanks to the testoFix probe holder (optional)

  • Completely enclosed plastic housing – particularly robust

Flue gas analysis with no stress, paper or shaky probes – the new testo 330i flue gas analyzer makes this possible. This instrument combines the proven measuring technology of its predecessor testo 330 LL with a revolutionary new method of operation.


Product Description

In order to commission and service heating systems as quickly and thoroughly as possible, you need an appropriate flue gas analyzer. A measuring instrument that delivers accurate results, whose probe is firmly secured in the flue gas duct at all times and which can also cope with larger systems or awkward measuring points without difficulty. A measuring instrument like the testo 330i.

Embodying the current trends in flue gas analysis

The testo 330i flue gas analyzer combines precision measuring technology with innovative operation. Its H2-compensated CO sensor means that you can also use this version of the testo 330i to carry out official acceptance test measurements on heating systems.
At the core of the flue gas analyzer is the technology of the testo 330 LL, which has been proven in practice a thousand times over, with the following features:
  • User-replaceable long-life sensors with a service life of up to 6 years. This saves at least one sensor replacement over the instrument's typical useful life
  • TÜV-tested according to 1st German Federal Immission Control Ordinance (BImSchV) and EN 50379, Parts 1-3
  • Integrated draught and gas zeroing without removing the probe – the probe can remain in the flue during zeroing
  • Fresh air dilution upon exceeding a CO threshold value up to 30,000 ppm
The instrument's completely redesigned method of operation is just as significant when it comes to your day-to-day work: operation of the measuring instrument and the display and documentation of readings are implemented wirelessly via the testo 330i App on your smartphone. The flue gas analyzer is easy to control remotely via Bluetooth, from a distance of up to 5 metres. Also, this means that you always have the system's flue gas values to hand when needed. Once you have finished the measurement, you can add comments or photos to the protocol and send it to your customer or the office via e-mail.

Requirement: iOS 7.1 / Android 4.3 or newer. Mobile end device with Bluetooth 4.0.

Work more efficiently with practical accessories

We developed the testoFix probe holder so that you no longer have to be concerned about whether the probe is firmly secured in the pipe. This optional accessory can be attached to the flue gas duct quickly and easily, and holds the probe securely in the centre of flow at all times. testoFix also serves as a fall-proof attachment system for the testo 330i flue gas analyzer. However, the measuring instrument also features extra-strong magnets and can therefore be attached to the burner in the usual way. Incidentally, the hose between probe and flue gas analyzer is somewhat shorter than on previous Testo probes and is particularly flexible, which makes it considerably easier both to work with the measuring instrument and to stow it away in the case.

Delivery Scope

testo 330i flue gas analyzer with long-life gas sensors, 3 slots and integrated draught and gas zeroing. Includes H2-compensated CO sensor, O2 measuring cell, rechargeable battery and calibration protocol.

Technical Data

General technical data


720 g (excluding battery)


270 x 160 x 57 mm

Operating temperature

-5 to +45 °C

Power supply

Rech. batt. block 3.7 V / 2.6 Ah; Mains unit 6 V / 1.2 A (optional)

System requirements

requires iOS 7.1 or newer; requires Android 4.3 or newer; requires mobile end device with Bluetooth 4.0

Maximum memory

500000 readings

Storage temperature

-20 to +50 °C

Differential Pressure - Piezoresistive

Measuring range

0 to 300 hPa


±0.5 hPa (0.0 to +50.0 hPa)

±1 % of mv (+50.1 to +100.0 hPa)

±1.5 % of mv (Remaining Range)


0.1 hPa

Flue gas O₂

Measuring range

0 to 21 Vol.%


±0.2 Vol.%


0.1 Vol.%

Flue gas CO (with H₂-compensation)

Measuring range

0 to 8000 ppm


±10 ppm or ±10 % of mv (0 to 200 ppm)

±20 ppm or ±5 % of mv (201 to 2000 ppm)

±10 % of mv (201 to 8000 ppm)


1 ppm

CO determination (with H₂-compensation), automatic dilution

Measuring range

0 to 30000 ppm


±200 ppm or ±20 % of mv (0 to 30000 ppm)


1 ppm

Flue gas NO

Measuring range

0 to 3000 ppm


±5 ppm (0 to 100 ppm)

±5 % of mv (101 to 2000 ppm)

±10 % of mv (2001 to 3000 ppm)


1 ppm


Differential Pressure flue gas Draught - Piezoresistive

Measuring range

-9.99 to +40 hPa


±0.02 hPa or ±5 % of mv (-0.50 to +0.60 hPa)

±0.03 hPa (+0.61 to +3.00 hPa)

±1.5 % of mv (3.01 to +40.00 hPa) (the greater value applies)


0.01 hPa


Measuring range

-40 to +1200 °C


±0.5 °C (0.0 to +100.0 °C)

±0.5 % of mv (Remaining Range)


0.1 °C (-40 to +999.9 °C)

1 °C (Remaining Range)

dependent on the thermocouple in the flue gas probe

Flue gas degree of effectivity, Eta (calculated)

Measuring range

0 to 120 %


0.1 %

Flue gas loss (calculated)

Measuring range

0 to 99.9 %


0.1 %

Flue gas CO₂ calculation (calculated from O₂)

Measuring range

Display range 0 to CO₂ max


±0.2 Vol.%


0.1 Vol.%




Product sets

testo 330i – flue gas set 

Order Number: 0563 3000 70


Order Number: 0563 3000 71


Differential pressure measurement

You can use the testo 330i flue gas analyzer to check the gas supply on gas boilers. You can therefore measure gas flow pressure and gas resting pressure in order to ensure that the system can be commissioned. You can also use the data specified by the manufacturer for the nozzle pressure to tailor the appliance output to the heat requirement.

Flue gas analysis and flue gas measurement

The testo 330i is equipped with two long-life sensors for measuring O2 and CO and can optionally be upgraded with an NO sensor. Flue gas and draught are measured in parallel, so all relevant flue gas parameters are displayed simultaneously on the smartphone.

O2 supply air measurement

In balanced flue systems, you can use the testo 330i flue gas analyzer to check whether there is a leak in the flue gas system. Measure the O2 content of the combustion air in the dual wall clearance to ensure that no flue gas is getting into the combustion air supply, thus preventing damage due to condensate or impairment of the combustion process.


Product Brochures



  • Firmware testo 330i  (v2.11, 3.6 MB) If the firmware update does not start under Windows 8.1 or Windows 10, a new bootloader must be installed on the measuring device once.
    A description and all necessary files can be found under the search term: Update-Kit / Bootloader

  • Testo ZIV driver ZIV 2000 for testo 320 and testo 330  (8.8 MB) Testo ZIV driver in the 2000 version. The Testo ZIV driver is used to connect the testo 320 and testo 330 measuring instruments to an application program (sweeping district administration program) according to the interface Version 2.0 defined by the Zentralverband des Schornsteinfegerhandwerks (Central Association of Chimney Sweeps, ZIV). Please check with the manufacturer of your application program as to whether this interface is supported. If Microsoft .NET Framework 4.0 has not been installed on the computer, it must be downloaded from the Microsoft website and installed on the system.