Materials Testing

Entry-level flue gas analyzer

  • Battery lifetime up to 10 hours
  • Fast sensor zeroing in only 30 seconds
  • Illuminated display
  • Documentation of measurement results via printer with infrared interface

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Accurate readings, rugged design, easy-to-use: That’s what you as a professional want from this flue gas analyzer so that you can carry out quick and reliable checks on heating systems.

And that’s exactly what you get with the testo 310 flue gas analyzer.

The testo 310 entry-level flue gas analyzer. For reliable heating system checks.

The testo 310 has an easy-to-use menu guide, four integrated menus for flue gas, draft, CO ambient air and pressure measurements, a large, easy-to-read display and a backlight for use in all lighting conditions.

But that is by no means all. The compact flue gas analyzer has a wide range of useful features that make it the ideal companion for plumbing and heating fitters. Thanks to the built-in magnet, it can stick to almost any metal object, like a burner for example, leaving both hands free for other tasks. The sensor can be zeroed in as little as 30 seconds and the sensor filter is just as easy to replace. In addition to that, the device has a rugged design which protects it against impact and damage and an easy-to-empty condensate collection tank.

To round things off, the readings can also be transferred directly to your testo turbo printer (optional) via the analyzer’s infrared interface, allowing you to print out on site.

What’s included

testo 310 flue gas analyzer, rechargeable battery, calibration certificate for O2, CO, hPa and °C measurements, 7 in. conical sensor, silicone tube for pressure measurements, 10x particle filters, case.

Delivery Scope

testo 310 flue gas analyzer, rechargeable battery, calibration certificate for O2, CO, hPa and °C measurements, 7 in. conical sensor, silicone tube for pressure measurements, 5x particle filters, case.


Draught measurement in the flue gas duct

Draught measurement is actually a differential pressure measurement. This differential pressure occurs between two sub-areas as a result of a difference in temperature. This is turn generates a flow to compensate. In the case of flue gas systems, the difference in pressure is an indicator of the “chimney flue draught”. This is measured between the flue gas and ambient air at the measurement orifice at the core of the flue gas flow.

To ensure the flue gases are safely transported through the chimney there must be a differential pressure (chimney flue draught) for boiler systems that work with low pressure.

If the draught is permanently too high, the average flue gas temperature increases and therefore flue gas loss. The level of efficiency drops.

If the draught is permanently too low, oxygen may be lacking during combustion, resulting in soot and carbon monoxide. This will also cause a drop in the level of efficiency.

Ambient CO measurement in the heated environment

Carbon monoxide (CO) is a colorless, 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 hemoglobin 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 places often frequented by people (in our case, where the combustion systems for hot water generation are),and in the surrounding areas.

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) 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:

1. Ensuring the atmosphere is contaminated as little as possible by pollutants; and

2. 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 center of flow in the connecting pipe (in the center 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 authorized 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.


Temperature – TC Type K (NiCr-Ni)
Measuring range-20 to +100 °C
Accuracy±1 °C
Resolution0.1 °C
Reaction time< 50 s

Temperature (ambient temperature)

Temperature – TC Type J (Fe-CuNi)
Measuring range0 to +400 °C
Accuracy±1 °C (0 to +100 °C)

±1.5 % of mv (> 100 °C)

Resolution0.1 °C
Reaction time< 50 s

Temperature (flue gas)

Flue gas O₂
Measuring range0 to 21 Vol.%
Accuracy±0.2 Vol.%
Resolution0.1 Vol.%
Reaction time t₉₀30 s
Flue gas Draught
Measuring range-20 to +20 hPa
Accuracy±0.03 hPa (-3.00 to +3.00 hPa)

±1.5 % of mv (Remaining Range)

Resolution0.01 hPa
Flue gas degree of effectivity, Eta (calculated)
Measuring range0 to 120 %
Resolution0.1 %
Flue gas loss (calculated)
Measuring range0 to 99.9 %
Resolution0.1 %
Flue gas CO₂ calculation (calculated from O₂)
Measuring range0 to CO₂ max (Display range)
Accuracy±0.2 Vol.%
Resolution0.1 Vol.%
Reaction time t₉₀< 40 s
Pressure measurement
Measuring range-40 to +40 hPa
Accuracy±0.5 hPa
Resolution0.1 hPa
Flue gas CO (without H₂-compensation)
Measuring range0 to 4000 ppm
Accuracy±20 ppm (0 to 400 ppm)

±5 % of mv (401 to 2000 ppm)

±10 % of mv (2001 to 4000 ppm)

Resolution1 ppm
Reaction time t₉₀60 s
Ambient CO
Measuring range0 to 4000 ppm
Accuracy±20 ppm (0 to 400 ppm)

±5 % of mv (401 to 2000 ppm)

±10 % of mv (2001 to 4000 ppm)

Resolution1 ppm
Reaction time60 s
General technical data
Dimensions201 x 83 x 44 mm
Operating temperature-5 to +45 °C
Display typeLCD
Display functionBacklit 2-line display
Power supplyBattery: 1500 mAh, mains unit 5V/1A
Storage temperature-20 to +50 °C
Weight(with probe) Approx. 700 g