The Testo 320 Flue Gas Analyzer is a versatile measuring instrument for professionals working with heating systems, burners, radiators, and related combustion equipment. It combines multiple measurement functions in a single rugged device, helping technicians perform routine installation, inspection, commissioning, and servicing tasks efficiently.

The instrument is supplied with an O₂ sensor and can be configured with additional sensors, including CO and CO-low sensors. Based on measured parameters, the analyzer can calculate important combustion values such as CO₂, efficiency, and flue gas loss.

The Testo 320 features a high-resolution 240 × 320-pixel colour graphic display with country-specific, easy-to-follow menus. It can store up to 500 measurement values, making it convenient for documenting and reviewing measurement results.

Its rugged construction is intended for demanding daily use, while the integrated temperature sensor and optional pressure and flue gas probes provide flexibility for different heating-system applications. The instrument is also TÜV-tested according to EN 50379 Parts 1–3 and 1st BImSchV.