• Measures combustion efficiency, °C, O2, CO2, CO and flue draught
  • O2 range: 0 to 21% 0 to 4000 PPM CO range
  • Temperature range: -40 to 932°F
  • ±80" WC pressure differential
  • Backlit 4-line LCD display


The Testo 327 combustion analyzer is a basic efficiency analyzer designed for heating technicians installing or servicing burners, boilers, furnaces and other combustion appliances, testing to ensure each system's safe operation and efficiency.

This Testo 327 analyzer is rugged and reliable. A backlit 4-line LCD display guarantees an easy-to-read display even if lighting conditions are unfavorable. The 327 analyzers operate longer in the field with minimal routine maintenance. The durable sensors measure combustion efficiency, °C, O2, CO2, CO and flue draught. The unit is programmed for 8 fuels so calculations account for variations in fuels.

The Testo 327 is available as the meter alone or in a number of packages designed to suit a wide range of needs.

Testo 327 Combustion Analyzer Specifications
Parameter Range Resolution
O2 (Oxygen) 0 to 21 % 0.1 %
CO (Carbon Monoxide) 0 to 4,000 PPM 1 PPM
Temperature -40 to 932°F 0.1°F
Pressure (Differential) ±80" WC 0.01" WC
Pressure (Draft) ±16" WC 0.001" WC
Calculates Combustion efficiency, excess air, CO2, CO-air free
Operating temp. range 23 to 113°F
Storage temp. range -4 to 120°
Dimensions 8.5" x 2.7" x 1.9"
Weight 1.1 lbs
Battery Li-Ion rechargeable battery (5 hrs)
Power Supply 120 VAC