Baxi Baxi Combi (624, 630)
Combi, natural gas
Combustion figures
| Figure | Natural gas (G20) |
|---|---|
CO₂ at high rate More infoHide infoPrinted as 9.0 + 0.3 – 0.2 (% maximum), the same for both sizes, in Tab.23 (9.3.12) and in Setting the gas valve (CO₂). Case front panel fitted. Checked in calibration (chimney sweep) mode after running the boiler for several minutes. | 9.0% +0.3 / −0.2 |
CO₂ at low rate More infoHide infoPrinted as 8.5 + 0.1 – 0.4 (% minimum), the same for both sizes, in Tab.23 (9.3.12) and in Setting the gas valve (CO₂). | 8.5% +0.1 / −0.4 |
Maximum CO More infoHide infoAt maximum and minimum rate, from the combustion procedure flow chart (Fig.47). | <350 ppm |
CO/CO₂ ratio More infoHide infoAt maximum and minimum rate (Fig.47, 9.1 and Setting the gas valve). | <0.004 |
O₂ More infoHide infoThe MI gives O₂ only for the flue integrity check at the air inlet test point. | Not given in MI |
Working inlet pressure More infoHide infoFrom Fig.43 (gas meter to valve). At the meter: 19–23 mbar. The text says the working pressure at the inlet gas pressure test point (A, on the gas cock) must be at least 18 mbar with the boiler at maximum rate. Nominal dynamic inlet pressure 20 mbar (G20). |
|
Gas rate at maximum More infoHide infoNatural gas (G20), with all other appliances and pilot lights off. Minimum rate (Qmin) 0.67 m³/h for both sizes (Tab.8). |
|
Flue integrity More infoHide infoAt the air inlet test point on the flue adaptor, boiler at maximum rate. | O₂ ≥ 20.6% CO₂ < 0.2% |
From 7679306 - 1 - 10082017
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
| Model | GC number | Gas |
|---|---|---|
| Baxi Combi 624 | 47-077-28 | NG |
| Baxi Combi 630 | 47-077-29 | NG |
Source: Baxi Combi 624 — 630 Installation and Service Manual, 7679306 - 1 - 10082017.
Sections: 3.1.3 Gas category; 3.2.1 Technical information (Tab.5, Tab.8); 7.4.1 Check the operational (working gas inlet pressure and gas rate); 7.4.2 Checking combustion - chimney sweep mode; 9.1 General; 9.3.12 Gas valve (Tab.23, Setting the gas valve (CO₂)).
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.