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Baxi Checked against MI

Baxi MainEco Combi (24, 28, 35)

Combi, natural gas

Combustion figures

FigureNatural gas (G20)
CO₂ at high rate
More infoHide infoFront panel removed. Set and checked at full load and part load (MI 6.4.2, 6.4.3). The MI also says the full load value must be 0.4% higher than the part load value, which the two printed ranges do not always give (e.g. 9.15% and 9.05%). Analyser accuracy at least ±0.25% CO₂.
Between 9.15 and 9.50%
CO₂ at low rate
More infoHide infoFront panel removed (MI 6.4.2, 6.4.3).
Between 8.70 and 9.05%
Maximum CO
More infoHide infoAt maximum and minimum rate, probe in the flue gas test point, after the flue integrity check (MI 6.4.2 flowchart).
< 350 ppm
CO/CO₂ ratio
More infoHide infoAt maximum and minimum rate (MI 6.4.2 flowchart).
< 0.004
O₂
Not given in MI
Working inlet pressure
More infoHide infoGas inlet pressure G20, min to max; connecting pressure G20 20 mbar (MI 4.6). Measurement point not stated in MI. MI 6.4.1 says to check the supply pressure at test point C on the gas inlet pipe against the rating plate.
17–23 mbar
Gas rate at maximum
More infoHide infoGas consumption G20, max (MI 4.6).
Combi 24
2.54 m³/h
Combi 28
2.98 m³/h
Combi 35
3.68 m³/h
Flue integrity
More infoHide infoAt the air inlet test point, boiler at maximum rate (MI 6.4.2 flowchart).
O₂ ≥ 20.6%
CO₂ < 0.2%

From 02092014 - 7619497-02

Enter service mode for high and low rate

High rate

Steps not added yet. Follow the MI.

Low rate

Steps not added yet. Follow the MI.
Ending the test: follow the MI.

Models and GC numbers

ModelGC numberGas
MainEco Combi 2447-075-93NG
MainEco Combi 2847-075-94NG
MainEco Combi 3547-075-95NG

Source: Baxi MainEco Combi and System 24-28-35 / 18-24 Installation and Service Manual, 02092014 - 7619497-02.

Sections: 2.4.1 Certifications; 4.6 Technical specifications; 6.4.1 Gas circuit; 6.4.2 Checking combustion; 6.4.3 Setting the air/gas ratio; 8.2.7 Checking combustion.

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Check these figures against the MI for the appliance in front of you, matched by GC number and manual date. Combustion work needs a calibrated analyser and a Gas Safe registered engineer.