testo 330 – Advanced flue gas analyzer with O₂, CO/H₂ and NO sensors and Bluetooth printer

The testo 330 is an advanced flue gas analyzer designed to give HVAC/R professionals clear insights and reliable results in increasingly complex working environments. The large 5.5" IPS touchscreen with app-like interface guides you step by step through flue gas and efficiency measurements, minimizes setup time and reduces operating errors in the field.
This flue gas analyzer is equipped with a Testo O₂ sensor, a high-performance CO/H₂ sensor and an integrated NO sensor. In combination with active dilution, the platform offers an extended CO range up to 40,000 ppm, enabling safe and stable measurements even at higher CO concentrations. The additional NO channel supports detailed combustion optimization and emissions assessment, particularly on modern low-NOx and high-efficiency systems. With measurement ranges tailored to typical combustion applications and automatic zeroing, the instrument delivers stable and accurate readings for O₂, CO, NO, draft, efficiency, flue gas loss and more – even under demanding conditions. Robust design (IP40), a proven sensor platform developed by Testo and TÜV-tested flue gas probes ensure long term reliability in daily field use.
Thanks to its integrated Bluetooth interface, the testo 330 connects seamlessly to the testo Smart App and to up to four wireless probes, enabling remote control, second screen operation and the integration of temperature, differential pressure, CO and CO₂ measurements.
Measurement data is stored in the large internal memory and can be synchronized via testo Smart Connect for centralized data management across jobs, devices and teams. A powerful rechargeable battery with fast USB-C charging provides up to 10 hours of operation, ensuring the analyzer is ready for a full working day.

O₂	Measuring range 0 to 21 Vol.%
Accuracy ±0.2 Vol.% ±1 Digit
Resolution 0.1 Vol.%

Measuring range

0 to 21 Vol.%

Accuracy

±0.2 Vol.% ±1 Digit

Resolution

0.1 Vol.%

CO (with H₂ compensation)	Measuring range 0 to 10000 ppm
Accuracy ±20 ppm or ±5 % of mv (201 to 2000 ppm) ±1 Digit ±10 ppm or ±10 % of mv (0 to 200 ppm) ±1 Digit ±10 % of mv (2001 to 10000 ppm) ±1 Digit
Resolution 1 ppm

Measuring range

0 to 10000 ppm

Accuracy

±20 ppm or ±5 % of mv (201 to 2000 ppm) ±1 Digit

±10 ppm or ±10 % of mv (0 to 200 ppm) ±1 Digit

±10 % of mv (2001 to 10000 ppm) ±1 Digit

Resolution

1 ppm

CO (with H₂ compensation, with active dilution)	Measuring range 0 to 40000 ppm
Accuracy ±100 ppm or ±10 % of mv ±1 Digit
Resolution 1 ppm

Measuring range

0 to 40000 ppm

Accuracy

±100 ppm or ±10 % of mv ±1 Digit

Resolution

1 ppm

Flue Gas NO	Measuring range 0 to 3000 ppm
Accuracy ±5 ppm (0 to 100 ppm) ±1 Digit ±10 % of mv (2001 to 3000 ppm) ±1 Digit ±5 % of mv (101 to 2000 ppm) ±1 Digit
Resolution 1 ppm

Measuring range

0 to 3000 ppm

Accuracy

±5 ppm (0 to 100 ppm) ±1 Digit

±10 % of mv (2001 to 3000 ppm) ±1 Digit

±5 % of mv (101 to 2000 ppm) ±1 Digit

Resolution

1 ppm

Flue Gas Draft	Measuring range -4.00 to +16 InH₂O / -9.99 to +40 hPa
Accuracy ±1.5 % of mv (+1.20 to +16 InH₂O) ±1 Digit / ±1.5 % of mv (+3.01 to +40 hPa) ±1 Digit ±0.01 InH₂O (0.0 to +1.20 InH₂O) ±1 Digit / ±0.02 hPa (0.1 to +3.00 hPa) ±1 Digit ±0.002 InH₂O (0 to 0.0 InH₂O) ±1 Digit / ±0.005 hPa (0 to 0.1 hPa) ±1 Digit
Resolution 0.00 InH₂O Remaining Range / 0.01 hPa Remaining Range 0.000 InH₂O (0 to 0.0 InH₂O)

Measuring range

-4.00 to +16 InH₂O / -9.99 to +40 hPa

Accuracy

±1.5 % of mv (+1.20 to +16 InH₂O) ±1 Digit / ±1.5 % of mv (+3.01 to +40 hPa) ±1 Digit

±0.01 InH₂O (0.0 to +1.20 InH₂O) ±1 Digit / ±0.02 hPa (0.1 to +3.00 hPa) ±1 Digit

±0.002 InH₂O (0 to 0.0 InH₂O) ±1 Digit / ±0.005 hPa (0 to 0.1 hPa) ±1 Digit

Resolution

0.00 InH₂O Remaining Range / 0.01 hPa Remaining Range

0.000 InH₂O (0 to 0.0 InH₂O)

Temperature	Measuring range -40° to 2192 °F / -40 to +1200 °C
Accuracy ±0.9 °F (32° to 212.0 °F) / ±0.5 °C (0 to +100.0 °C) ±1 Digit ±0.5 % of mv (Remaining Range) ±1 Digit
Resolution 1.0 °F (Remaining Range n2{+#0} {%S2}) / 1 °C (Remaining Range) 0.1 °F (-40° to 1831.8 °F) / 0.1 °C (-40 to +999.9 °C)

Measuring range

-40° to 2192 °F / -40 to +1200 °C

Accuracy

±0.9 °F (32° to 212.0 °F) / ±0.5 °C (0 to +100.0 °C) ±1 Digit

±0.5 % of mv (Remaining Range) ±1 Digit

Resolution

1.0 °F (Remaining Range n2{+#0} {%S2}) / 1 °C (Remaining Range)

0.1 °F (-40° to 1831.8 °F) / 0.1 °C (-40 to +999.9 °C)

Efficiency testing (η)	Measuring range 0 to 120 %
Resolution 0.1 %

Measuring range

0 to 120 %

Resolution

0.1 %

Flue gas loss	Measuring range 0 to 99.9 %
Resolution 0.1 %

Measuring range

0 to 99.9 %

Resolution

0.1 %

CO₂ (calculated from O₂)	Measuring range 0 to CO₂ max (Display range)
Accuracy ±0.2 Vol.% ±1 Digit
Resolution 0.1 Vol.%

Measuring range

0 to CO₂ max (Display range)

Accuracy

±0.2 Vol.% ±1 Digit

Resolution

0.1 Vol.%

Pressure measurement	Measuring range -40 to +80 InH₂O / -100 to +200 hPa
Accuracy ±1.5 % of mv (+100.1 to +80 InH₂O) ±1 Digit / ±1.5 % of mv (+100.1 to +200 hPa) ±1 Digit ±0.2 InH₂O (0 to +20.0 InH₂O) ±1 Digit / ±0.5 hPa (0 to +50.0 hPa) ±1 Digit ±1 % of mv (+20.0 to +40.0 InH₂O) ±1 Digit / ±1 % of mv (+50.1 to +100.0 hPa) ±1 Digit
Resolution 0.00 InH₂O / 0.01 hPa

Measuring range

-40 to +80 InH₂O / -100 to +200 hPa

Accuracy

±1.5 % of mv (+100.1 to +80 InH₂O) ±1 Digit / ±1.5 % of mv (+100.1 to +200 hPa) ±1 Digit

±0.2 InH₂O (0 to +20.0 InH₂O) ±1 Digit / ±0.5 hPa (0 to +50.0 hPa) ±1 Digit

±1 % of mv (+20.0 to +40.0 InH₂O) ±1 Digit / ±1 % of mv (+50.1 to +100.0 hPa) ±1 Digit

Resolution

0.00 InH₂O / 0.01 hPa

Ambient CO	Measuring range 0 to 2000 ppm (internal/flue gas probe) 0 to 500 ppm (external with CO probe)
Accuracy ±3 ppm (0 to 29 ppm) ±1 Digit (external with CO probe) ±10 % of mv (101 to 2000 ppm) ±1 Digit (internal/flue gas probe) ±10 ppm (0 to 100 ppm) ±1 Digit (internal/flue gas probe) ±10 ppm (30 to 500 ppm) ±1 Digit (external with CO probe)
Resolution 1 ppm (external with CO probe) 1 ppm (internal/flue gas probe)

Measuring range

0 to 2000 ppm (internal/flue gas probe)

0 to 500 ppm (external with CO probe)

Accuracy

±3 ppm (0 to 29 ppm) ±1 Digit (external with CO probe)

±10 % of mv (101 to 2000 ppm) ±1 Digit (internal/flue gas probe)

±10 ppm (0 to 100 ppm) ±1 Digit (internal/flue gas probe)

±10 ppm (30 to 500 ppm) ±1 Digit (external with CO probe)

Resolution

1 ppm (external with CO probe)

1 ppm (internal/flue gas probe)

Differential Pressure 4 Pa measurement - Piezoresistive	Measuring range -50 to +0 InH₂O / -50 to +50 Pa
Accuracy ±0.0 InH₂O (< 0 InH₂O) ±1 Digit / ±0.3 Pa (< 10 Pa) ±1 Digit ±3.0 % of mv (Remaining Range) ±1 Digit
Resolution 0.0 InH₂O / 0.1 Pa

Measuring range

-50 to +0 InH₂O / -50 to +50 Pa

Accuracy

±0.0 InH₂O (< 0 InH₂O) ±1 Digit / ±0.3 Pa (< 10 Pa) ±1 Digit

±3.0 % of mv (Remaining Range) ±1 Digit

Resolution

0.0 InH₂O / 0.1 Pa

General technical data	Operating humidity 15 to +90 %rH (non-condensing)
Weight approximately 24 oz. / approximately 685 g
Dimensions approximately 9 x 4 x 2 in. (LxWxH) (incl. probe connection) / approximately 227 x 102 x 47 mm (LxWxH) (incl. probe connection)
Operating temperature 23° to 113 °F
Protection class IP40
Connectable probes 4 x digital Bluetooth® probe or testo Smart Probe; connectable: Smart Probes (°C, Delta P), CO + CO₂ probes
System requirements requires iOS 17 or newer; requires Android 14 or newer
Battery life 10 h
Display type 5.5" IPS touch display, HD 1280 x 720 pixels
Power supply Rechargeable battery, USB mains unit
Guarantee 48 + 12 months (with app registration)
Operating time ~60 min (25 °C)
Maximum ≤1,000,000 readings
Interface Bluetooth® 4.2
Radio range Up to 100 m (with no obstructions)
Battery charging option Quick charge
Battery charging time 20 min
Storage temperature -4° to 122 °F / -20 to +50 °C
Charging temperature 32 to +95 °F / 0 to +35 °C

Operating humidity

15 to +90 %rH (non-condensing)

Weight

approximately 24 oz. / approximately 685 g

Dimensions

approximately 9 x 4 x 2 in. (LxWxH) (incl. probe connection) / approximately 227 x 102 x 47 mm (LxWxH) (incl. probe connection)

Operating temperature

23° to 113 °F

Protection class

IP40

Connectable probes

4 x digital Bluetooth® probe or testo Smart Probe; connectable: Smart Probes (°C, Delta P), CO + CO₂ probes

System requirements

requires iOS 17 or newer; requires Android 14 or newer

Battery life

10 h

Display type

5.5" IPS touch display, HD 1280 x 720 pixels

Power supply

Rechargeable battery, USB mains unit

Guarantee

48 + 12 months (with app registration)

Operating time

~60 min (25 °C)

Maximum

≤1,000,000 readings

Interface

Bluetooth® 4.2

Radio range

Up to 100 m (with no obstructions)

Battery charging option

Quick charge

Battery charging time

20 min

Storage temperature

-4° to 122 °F / -20 to +50 °C

Charging temperature

32 to +95 °F / 0 to +35 °C

General technical data	Weight 136.86 oz. / 3880 g
Dimensions 20.5 x 15.7 x 5.1 in. (LxWxH) / 520 x 400 x 130 mm (LxWxH)
Housing Plastic
Product colour Black

Weight

136.86 oz. / 3880 g

Dimensions

20.5 x 15.7 x 5.1 in. (LxWxH) / 520 x 400 x 130 mm (LxWxH)

Housing

Plastic

Product colour

Black

General technical data	Weight 0.42 oz. / 12 g
Dimensions height: 0.11 in., ø: 1.17 in. / height: 2.9 mm, ø: 29.7 mm
Product colour white

Weight

0.42 oz. / 12 g

Dimensions

height: 0.11 in., ø: 1.17 in. / height: 2.9 mm, ø: 29.7 mm

Product colour

white

General technical data	Storage temperature -4° to 122 °F / -20 to +50 °C Rechargeable battery storage temperature: ±0° to 95 °F / Rechargeable battery storage temperature: ±0 to +35 °C
Weight approximately 14.1 oz. (including rechargeable battery pack, paper roll, mains unit) / approximately 400 g (including rechargeable battery pack, paper roll, mains unit)
Dimensions 5.9 x 3.1 x 1.6 in. ((LxWxH)) / 150 x 80 x 41 mm (LxWxH)
Operating temperature 32° to 122 °F / 0 to +50 °C
EU-/EG-guidelines RED: 2014/53/EU
Alarmsignal by LED
Battery type Lithium-Ion rechargeable battery pack, 3500 mAh, 3.7 V
Warranty conditions https://www.testo.com/guarantee
Interface USB; NFC
Battery charging time 6 - 8,5 h
Battery life > 6 h (20 °C / 68 °F)
Interface printer Bluetooth® / IRDA
Print speed 30 mm/s

Storage temperature

-4° to 122 °F / -20 to +50 °C

Rechargeable battery storage temperature: ±0° to 95 °F / Rechargeable battery storage temperature: ±0 to +35 °C

Weight

approximately 14.1 oz. (including rechargeable battery pack, paper roll, mains unit) / approximately 400 g (including rechargeable battery pack, paper roll, mains unit)

Dimensions

5.9 x 3.1 x 1.6 in. ((LxWxH)) / 150 x 80 x 41 mm (LxWxH)

Operating temperature

32° to 122 °F / 0 to +50 °C

EU-/EG-guidelines

RED: 2014/53/EU

Alarmsignal

by LED

Battery type

Lithium-Ion rechargeable battery pack, 3500 mAh, 3.7 V

Warranty conditions

https://www.testo.com/guarantee

Interface

USB; NFC

Battery charging time

6 - 8,5 h

Battery life

> 6 h (20 °C / 68 °F)

Interface printer

Bluetooth® / IRDA

Print speed

30 mm/s

General technical data	Diameter probe shaft 0.315 in. / 8 mm
Cable length 7.218 ft. / 2.2 m
Length probe shaft 11.811 in. / 300 mm
Product colour Black
Diameter 0.236 in. / 6 mm
Temperature maximum 932 °F / 500 °C
Weight 19.47 oz. / 552 g

Diameter probe shaft

0.315 in. / 8 mm

Cable length

7.218 ft. / 2.2 m

Length probe shaft

11.811 in. / 300 mm

Product colour

Black

Diameter

0.236 in. / 6 mm

Temperature maximum

932 °F / 500 °C