Electronic Gas Flue Analyser

• Should confirm to BS EN 50379-3 (BS7927:1998)
• Should measure:
  • O2 oxygen
  • CO carbon monoxide in parts per million (ppm)
  • CO2 carbon dioxide
  • CO/CO2 ratio
  • Temperature
  • NO Nitrogen monoxide
  • Pressure
  • Excess air
  • Combustion efficiency
• Most analysers do not measure the absolute levels of CO and O2
• Analysers are not designed for continuous measurement
• Should not be used to identify leakage of combustion products
• Not all analysers can record the maximum CO reading
• Accuracy
  • Readings at or below 20ppm - ±3ppm
  • Readings above 20ppm - ±5%

Gas Analyser Preparation and Use

• A small bottle of calibration gas can be used to check the sensor
• Analyser reading can be affected by:
  • cooking activities
  • cleaning fluids
  • polishes and paints
• Multi-hole sample probe for use on gas cookers
• "Zero" procedure - O2 reading in outdoor air is 20.9%
• Do not smoke before or during the test
• Preparation for testing:
  • Position sampling probe 2m above the floor level and 1m away from appliances
  • Record the level of CO over 15min period
    • there shouldn't be any rise of CO level
• Testing
  • With only one appliance on measure the CO level
  • If at any time the CO reading exceeds 30ppm (except when testing cookers):
    • stop the test
    • turn off all appliances
    • open all windows and doors to ventilate the room
    • and vacate the room under test
  • Flueless Cookers Testing
    • Ensure that ventilation is unobstructed
    • Put 2 saucepan (with 1 liter of water; 160 to 220mm base) on 2 largest pan-supports
    • Place the grill pan in its highest position under the grill
    • Light the grill, oven (at mid-range) and 2 hotplate burners at maximum
      • Turn hotplates down to simmer when water boils
      • Turn the grill off after 30min
    • Record CO levels at 1min intervals:
      • Reading doesn't exceed 30ppm - pass
      • Reading doesn't exceed 30ppm for 20min and falling not exceeding 90ppm - pass
      • Reading exceeds 90ppm - fail
  • Flueless Water Heaters
    • Light the appliance at maximum rate for 5 minutes recording the CO levels at 1 min intervals
  • Flueless Space Heaters
    • Light the appliance at maximum rate for 30 minutes recording the CO levels at 1 min intervals

Combustion Performance (CO/CO2 ratio) Action Levels