The Testo 340 provides the information to understand your process, enabling you to make informed combustion decisions. It is the ideal tool to confirm proper set-up, tune your boiler, and help identify emission problems.

Rugged, reliable, and accurate, the 340 combines the portability of a small gas analyzer with the measuring capability and features normally only found in much larger analyzers, including the ability to measure up to four gases simultaneously, 18 pre-programmed fuels and 10 user-defined fuels, and and integrated pressure sensor to measure draft and differential pressure.  Other industry-leading features include:

  • 4-gas simultaneous measuring capability

  • Field-replaceable pre-calibrated gas sensors mean zero downtime

  • 18 pre-programmed fuel parameters, plus 10 user-defined fuels

  • Automatic Sensor Protection keeps prevents analyzer damage

  • Integrated pressure sensor measures draft or differential pressure

  • Measure exhaust gas and flow velocity for accurate flow readings

  • Simple, intuitive operation and rugged construction

The Testo 340 is the ultimate in simple, reliable testing. Get pinpoint accuracy in a small, lightweight, and portable package. Simplify your testing - choose Testo. 



Stationary engine exhaust, when uncontrolled, can have very wide concentration ranges. As a result, both CO and NO2 can fluctuate significantly. The on-board dilution system and the replaceable interference filters keep the sensors secure and your readings accurate.

The 340 measures both NO and NO2 for perfect lean-burn engine set-up. High exhaust pressures and heavy particulate loading are easily controlled with the special pressure relief valve (standard) and sintered particulate filters (optional Engine Probe required).

In addition, the patented dilution system extends sensor ranges (specifically needed for engine testing) and provides greater sensor protection. It also gives a true CO measurement, while eliminating the cross-sensitivity problems other analyzers exhibit in their CO measurements.

Hands down, the 340 is the most portable, most accurate Engine Testing instrument on the market today. 


No more guessing, no more inaccurate measurements. The advanced onboard diagnostics system monitors system performance in real time, allowing for instant notification of instrument faults or issues. Simply go to the diagnostics screen to see instrument status, ensuring you get an accurate reading the first time, every time. 

  • Automatic leak detection checks probe hose and gas path integrity

  • Check battery status, including time remaining before recharge

  • Review the pump flow rate (liters/min)

  • Error statuses with description and remedial actions required

  • Find last service/maintenance date

  • Graphic representation of sensor calibration data

  • Condensate trap water level indicator


From combustion tuning to compliance testing data, easyEmission provides extraordinary data management capabilities. See the power of an intuitive user interface and exclusive features, including:

  • Real-time monitoring window, allowing testing in the background

  • Export data to Microsoft Excel or create a PDF

  • Clear, graphical information display

  • Generate testing reports

  • Calculate maximum, minimum, and average values

  • User-defined reports and printouts

  • Manage data by customer and site location

  • Control your 340 via Bluetooth




From engine testing under high particulate loads, to burner testing in extreme heat, Testo has a probe for your application,and every probe and hose assembly is constructed of the highest quality material. 

  • Cam-lock connection prevents accidental disconnection

  • Heat-resistant Teflon hoses come standard

  • Probe lengths from 12-28 inches standard

  • Optional hose extensions give 25-foot reach

And for extreme tuning applications, Testo offers probe lengths up to 9 feet,  and temperature resistance up to 3200°F. For your testing, trust the quality and accuracy of Testo.