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British Gas Checked against MI

British Gas CC1 combi (ZWB 7-29 CC1)

Combi, natural gas and LPG

Combustion figures

FigureNatural gas (G20)LPG (G31)
CO₂ at high rate
More infoHide infoNo tolerance given. Measured at the flue gas testing point (234) with the hot water control set so the display shows 2. (max. rated heat output). Same figures in Technical data and Table 17.
9.2%10.8%
CO₂ at low rate
More infoHide infoNo tolerance given. Measured with the display showing 1. (min. rated heat output).
8.8%10.5%
Maximum CO
Not given in MINot given in MI
CO/CO₂ ratio
Not given in MINot given in MI
O₂
Not given in MINot given in MI
Working inlet pressure
More infoHide infoThe MI says natural gas appliances must not be operated if the supply pressure is below 18 mbar or above 24 mbar (Technical data gives 20 mbar). LPG appliances must not be operated if the supply pressure is not 37 mbar at the inlet to the appliance (5.1), or is below or above 37 mbar at the gas supply pressure testing point (7). The MI calls it the gas supply pressure test point (Fig. 2, item 7), drawn on the gas valve.
Gas valve test point
18–24 mbar
Appliance inlet
37 mbar
Gas valve test point
37 mbar
Gas rate at maximum
More infoHide infoAfter 10 minutes from lighting.
3.1 m³/h2.3 kg/h
Flue integrity
More infoHide infoIn the combustion air, at testing point 234.1, in chimney sweep mode (max. rated heat output or the set heating output). For type C13 or C33 flue systems. The MI says O₂ must not be less than 20,6% and CO₂ must not exceed 0,2%.
O₂ ≥ 20.6%
CO₂ ≤ 0.2%
O₂ ≥ 20.6%
CO₂ ≤ 0.2%

From 6 720 610 599 GB (03.02)

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
ZWB 7-29 CC147-108-05Not stated

Source: CC1 Installation and Servicing Instructions, 6 720 610 599 GB (03.02).

Sections: 1.9 Technical data; 5.1 Commissioning; 7 Converting the appliance to different gas types; 7.1 Setting the gas/air ratio; 7.2 Testing combustion air/flue gas at set heat output.

Spotted something wrong? Tell us.

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.