Testo 300+ Flue Gas Analyser
The Testo 300+ Flue Gas Analyser provides smart and easy flue gas measurement for heating systems. It simplifies daily tasks with its advanced features and user-friendly design. High-quality sensors, a responsive smart-touch display, and seamless documentation streamline your workflow.
Enhanced O2 and CO Sensors with 5 Year Lifespan!
In what ways does the Testo 300+ assist you?
Smart Operation: The smart-touch display operates like a smartphone, providing quick, intuitive access to all functions. Clearly structured measurement menus speed up results.
Effortless Documentation: Create and save PDF reports (including measurements, locations, and customer details) directly on the instrument. Customers can sign reports on-screen, and you can email them instantly via WLAN.
Enhanced Display: A large 5-inch HD touchscreen lets you see all system details clearly. You can view multiple readings or graphs at once.
Next-Generation Sensors: The Testo 300+ Flue Gas Analyser features a CO sensor that measures up to 8,000 ppm with H₂ compensation. The 5-year lifespan reduces downtime and maintenance costs.
Comprehensive Measurement: Accurately measures oxygen, flue and ambient carbon monoxide, nitric oxide (with optional sensor), draught, pressure, and temperature. Additional onboard calculations include CO₂, combustion ratio, efficiency (0–120%), and flue gas loss (0–99.9%).
Second-Screen Functionality: Use the Testo Smart App to monitor measurements remotely, even at a distance.
Bluetooth Integration: Supports Testo Smart Probes for measuring up to four parameters simultaneously. Compatible probes are available as accessories.
Rugged Design: Scratch-resistant touchscreen with protective film ensures durability across various environments. The analyser includes a 10-hour battery life and a 5-year warranty for reliable long-term use.
The Testo 300+ Flue Gas Analyser boosts productivity. It offers precise measurements and a user-friendly interface. Its advanced features make it a must-have tool for professionals.

Testo 300+ Key Features:
(0633 3004 95) Handset only - (O2, CO Sensor up to 8,000 ppm)
(0564 3004 12) Standard kit - (O2, CO sensor up to 8,000 ppm)
(0564 3004 13) Advanced Kit - (O2, CO sensor up to 8,000 ppm)
(300564 3004 01) Smart Kit - (O2, CO sensor up to 8,000 ppm, plus smart probes)
(300564 3004 02) Ultra Smart Kit - (O2, CO sensor up to 8,000 ppm, extended probe set and connectivity)
- For testing domestic gas and oil boilers
- Flue gas, tightness and let-by, differential temperature & pressure, ambient CO, and draught measurement menus
- 5-year sensors for reduced service costs
- 8,000 ppm CO sensor with H₂ compensation and automatic pump shut off to prevent over-ranging
- EN50379-1/3 and BS7967 compliant
- 20% H₂ ready
- Bluetooth USB adapter supplied for connectivity to Testo Smart Probes
What testing capabilities do you get with the Heat Pump Kit?
(300564 3004 04) Heat pump kit - (O2, CO sensor up to 8,000 ppm)
- Heat Pump Kit is equipped to test domestic gas and oil boilers but also monobloc or split heat pumps too!
What comes with the Testo 300+?
Handset Only (0633 3004 95):
- Testo 300+ Flue Gas Analyser Handset only - (O2, CO Sensor up to 8,000 ppm)
- (0633 3004 40) Enhanced 5-year lifespan sensors – O2 and H₂ compensated CO sensor
- (0554 1105) USB mains unit (including cable)
- (0554 3004) Bluetooth connector
Standard Kit (0564 3004 12):
- Testo 300+ Flue Gas Analyser (O₂ and CO sensor up to 8,000 ppm)
- Compact basic flue gas probe, 180 mm; Ø 6 mm; Tmax. 500 °C with 1.5 m hose and fixing cone
- USB mains unit and Bluetooth connector
- Soft carry case
Advanced Kit (0564 3004 13):
- Testo 300+ Flue Gas Analyser with 5-year O₂ and CO sensors
- Compact flue gas probe, 180 mm, 500 °C
- Additional temperature probe for flow/return measurement
- USB mains unit, hose set, Bluetooth connector
- Robust carry case
Smart Kit (300564 3004 01):
- Testo 300+ Flue Gas Analyser with O₂ and CO sensors
- Compact flue gas probe
- Set of Testo Smart Probes (for pressure and temperature)
- Bluetooth connectivity and Smart App integration
- Carrying case with compartments for all accessories
Ultra Smart Kit (300564 3004 02):
- Testo 300+ Flue Gas Analyser with O₂ and CO sensors
- Extended probe set for more demanding applications
- Wider range of Smart Probes for gas, pressure, and temperature analysis
- USB mains unit, Bluetooth connectivity
- Professional-grade hard carry case
Heat Pump Kit:
- Testo 300+ Flue Gas Analyser (O₂ and CO sensor up to 8,000 ppm)
- Flue gas probe, hose set, and USB mains unit
- 1 x Testo 510i Smart probe manometer
- 2 x Testo 115i Smart probe pipe clamp thermometers
- 1 x Testo 550i smart digital manifold
- Bluetooth connector and soft carry case
Testo 300+ Kit Comparison
Kit | Main Inclusions |
Advanced Kit (0564 3004 13) | - Testo 300+ with O₂ & CO sensors (8,000 ppm H₂ compensated) - Compact flue gas probe (180 mm, 500 °C) - Additional temperature probe for flow/return - USB mains unit, hose set, Bluetooth connector - Robust carry case |
Smart Kit (300564 3004 01) | - Testo 300+ with O₂ & CO sensors - Compact flue gas probe - Testo Smart Probes (pressure & temperature) - Bluetooth integration & Smart App support - Carrying case with compartments |
Ultra Smart Kit (300564 3004 02) | - Testo 300+ with O₂ & CO sensors - Extended probe set for demanding applications - Wider range of Smart Probes (gas, pressure, temperature) - USB mains unit & Bluetooth connectivity - Professional-grade hard carry case |
For decades, Testo have been a trusted name in flue gas measuring instruments. As a leading UK manufacturer for over 40 years, they provide high-quality products designed for accurate and reliable measurements.