testo 320B - Flue Gas Analyser (Advanced Set)

Order-Nr.  0563 3223 72

  • Single and robust connection from the probe to the instrument

  • 5 applications with just one instrument: flue gas measurement, flue draught measurement, pressure measurement, ambient CO and differential pressure measurement 

  • Clear and simple colour menu - tests listed with text and icons 

  • Independently tested to EN50379 Parts 1-3

Flue gas measurement on heating systems with a compact flue gas analyser for oil and gas: the testo 320 basic features all the essential functions for carrying out flue gas analysis, flue draught and pressure measurements. In the set, you get the testo 320 basic flue gas analyser with practical accessories.

£ 730.00
incl. VAT £ 876.00

Product Description


The testo 320B Flue Gas Analyser is ideal for carrying out installation and maintenance work on heating systems. In conjunction with the supplied flue gas probe, the compact flue gas analyser can be used to measure flue gas, draught, pressure, ambient CO and differential temperature. In the set you also get practical accessories, to make handling easier.
With its self-explanatory menu guidance, the flue gas analyser is very easy to operate. It shows the readings on the high-resolution colour display, which is easy to read even when the light is poor. The memory of the flue gas analyser can record up to 20 measurement protocols. It is possible to export the measurement protocols in Excel optionally via mini-USB.
Quality that you can depend on: the testo 320B flue gas analyser is compliant according to EN 50379, Part 1-3.

testo 320B flue gas analysis set: reliable instrument, practical accessories

  • Ready to start measuring flue gas on heating systems: the testo 320 basic flue gas analyser is equipped with two sensors – an O2 and a CO sensor (without H2 compensation). In the case of CO measurement, the measuring range goes up to 4,000 ppm. For flue gas measurement, you need a compact or modular flue gas probe. A compact flue gas probe is included in the set. A temperature probe is integrated into the probe. All relevant flue gas measurement parameters can therefore be calculated: CO2 value, efficiency and flue gas loss. The flue gas analyser can also be used for flue draught measurements or pressure measurements
  • Changing probes is easy: the probes can be changed by the user. This means that you can order other probes specifically required for your flue gas analysis (e.g. multi-hole probe, dual wall clearance probe, flexible flue gas probe)
  • Single-hose connection: just one hand movement is needed to securely connect all channels for the flue gas measurement via the probe coupling (gas paths, draught, temperature probe integrated in the flue gas probe)
  • Long service life thanks to the long-life Li-ion rechargeable battery
  • Built-in magnets enable the flue gas analyser to be attached to the burner/boiler quickly and easily
  • Integrated condensate trap: easy to empty
  • Advantage of owning the set: in the set you get the flue gas analyser with compact flue gas probe, USB mains unit (with USB cable) and instrument case

Possible applications for the testo 320B flue gas analysis set

  • Flue gas measurement (focus on gas: combustion air temperature, flue gas temperature, O2, CO and CO2 concentration, flue gas loss, gas/air ratio, efficiency)
  • Gas flow and gas resting pressure (with optional hose connection set)
  • Differential temperature measurement to determine the spread between flow and return (with optional differential temperature set)
Designed especially for the UK market, the testo 320B supports the full range of fuels including natural gas, butane, propane, light oil, kerosene, heavy oil, wood pellets, coal, anthracite and coke. It benefits from improved robustness to deal with the rigours of the UK energy market including high quality sampling probes with non-kinking PTFE coated hose and unique connector.


Delivery Scope

testo 320B Flue Gas Analyser, incl. case, USB Charger, Flue Gas probe 180mm/300mm P-Type D=6mm, IRDA printer, Hose connection set, temp set and Spare particle filters.

Flue gas O₂

Measuring range

0 to 21 Vol.%


±0.2 Vol.%


0.1 Vol.%

Reaction time t₉₀

< 20 s

Flue gas Draught

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)


0.01 hPa


Measuring range

-40 to +1200 °C


±0.5 °C (0 to +100.0 °C)

±0.5 % of mv (Remaining Range)


0.1 °C (-40 to +999.9 °C)

1 °C (> +1000 °C)

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

0 to CO₂ max (Display range)


±0.2 Vol.%


0.1 Vol.%

Reaction time t₉₀

< 40 s

General technical data


240 x 85 x 65 mm

Operating temperature

-5 to +45 °C

Protection class


Display size

240 x 320 pixels

Display function

Colour graphic display

Power supply

Battery: 3.7 V / 2,400 mAh; Mains unit: 5 V / 1 A


Storage temperature

-20 to +50 °C


573 g

Accessories for probes

£ 22.00
incl. VAT £ 26.40


£ 142.00
incl. VAT £ 170.40


£ 59.00
incl. VAT £ 70.80
CPA 1 Accessory Kit

Order Number: 300554 1000

£ 185.00
incl. VAT £ 222.00

Accessories for measuring instrument

USB mains unit incl. cable

Order Number: 0554 1105

£ 36.50
incl. VAT £ 43.80
£ 22.00
incl. VAT £ 26.40


£ 77.00
incl. VAT £ 92.40

Printer and accessories

testo fast printer IRDA

Order Number: 0554 0549

£ 199.00
incl. VAT £ 238.80
£ 24.00
incl. VAT £ 28.80

Ambient CO measurement in the heated environment

Carbon monoxide (CO) is a colourless, odourless and taste-free gas, but also poisonous. It is produced during the incomplete combustion of substances containing carbon (oil, gas, and solid fuels, etc.). If CO manages to get into the bloodstream through the lungs, it combines with haemoglobin thus preventing oxygen from being transported in the blood; this in turn will result in death through suffocation. This is why it is necessary to regularly check CO emissions at the combustion points of heating systems and the surroundings.

Measuring the flue gas parameters of the burner (CO, O2, and temperature, etc.)

The flue gas measurement for a heating system helps to establish the pollutants released with the flue gas (e.g. carbon monoxide CO or carbon dioxide CO2) and the heating energy lost with the warm flue gas. In some countries, flue gas measurement is a legal requirement. It primarily has two objectives:


  • Ensuring the atmosphere is contaminated as little as possible by pollutants; and
  • energy is used as efficiently as possible.


Stipulated pollutant quantities per flue gas volume and energy losses must never be exceeded. Measurement in terms of results required by law takes place during standard operation (every performance primarily using the appliance). Using a Lambda probe (single hole or multi-hole probe), the measurement is taken at the centre of flow in the connecting pipe (in the centre of the pipe cross-section, not at the edge) between the boiler and chimney/flue. The measured values are recorded by the flue gas analyzer and can be logged either for print out or transfer to a PC at a later stage.

Measurement is taken by the installer at commissioning, and if necessary four weeks later by the flue gas inspector/chimney sweep, and then at regular intervals by the authorised service engineer.

Measuring pressure on burners (nozzle pressure, gas flow pressure, etc.)

Standard readings taken during services of domestic heating systems include checking the gas pressure on the burners. This involves measuring the gas flow pressure and gas resting pressure. The flow pressure, also called supplied pressure, refers to the gas pressure of the flowing gas and resting pressure of the static gas. If the flow pressure for gas boilers is slightly outside the 18 to 25 mbar range, adjustments must not be made and the boiler must not be put into operation. If put into operation nonetheless, the burner will not be able to function properly, and explosions will occur when setting the flame and ultimately malfunctions; the burner will therefore fail and the heating system will shut down.

Measuring temperatures on radiators

When measuring the temperature on radiators, the flow and return temperatures are recorded in particular and assessed by the tradesman. The flow temperature is defined as the temperature of a thermal transfer medium (e.g. water) that the system is supplied with. The temperature of the medium flowing out of the system is accordingly called the return temperature. To prevent losses within the heat distribution system and achieve a better level of efficiency in modern, heating technology, spot recording of flow and return temperatures is necessary at certain radiator pipes or screw fittings. Implementation of relevant measures ultimately leads to hydraulic adjustment on the basis of knowledge about the flow and return temperatures. This defines a procedure with which every radiator or heating circuit of a flat radiator within a heating system is supplied at a set flow temperature with the precise amount of heat needed to achieve the ambient temperature required for the individual rooms. Flawed operating conditions will result in considerable excess consumption of electricity and heating energy.