Baxi Duo-tec Combi ErP (24, 28, 33, 40, 28 LPG)
Combi, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoChecked in calibration mode at maximum rate, at the flue sampling test point, after running the boiler for several minutes. Case position not stated in MI. If CO₂ is reset at one rate, recheck the other rate. | 8.7% ± 0.2 | 10% ± 0.2 |
CO₂ at low rate More infoHide infoChecked in calibration mode at minimum rate (display reads 0). | 8.4% ± 0.2 | 9.8% ± 0.2 |
Maximum CO More infoHide infoAt both maximum and minimum rate, at the flue gas test point (commissioning flow chart, MI 10.2). The flow chart isn’t split by gas type. | < 350 ppm | < 350 ppm |
CO/CO₂ ratio More infoHide infoAt both maximum and minimum rate (MI 10.2). MI 12.1 and 14.1 also say it must be less than 0.004. | < 0.004 | < 0.004 |
O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoNG: the gas valve minimum is from fault finding chart I (MI 17.0), which doesn’t name the gas type. Technical data (MI 4.1) gives NG inlet pressure 20 mbar, and MI 17.1 says the preferred minimum gas pressure is 20 mbar; measurement point not stated in MI for either. MI 10.3 says to check at the inlet gas pressure test point on the gas valve at maximum rate, but gives no figure there. LPG (propane G31, MI 18.0): Measurement point not stated in MI. |
| 37 mbar |
Gas rate at maximum More infoHide infoAfter 10 minutes (MI 4.1). MI 10.3.8 gives the same NG figures, measured with other appliances and pilot lights off. LPG is the 28 LPG model only, propane G31 (MI 18.0). |
| 2.25 kg/h |
Flue integrity More infoHide infoAt the air inlet test point, boiler at maximum rate (MI 10.2). | O₂ ≥ 20.6% CO₂ < 0.2% | O₂ ≥ 20.6% CO₂ < 0.2% |
From 7219665 - 02 (10/15)
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 |
|---|---|---|
| Duo-tec 24 Combi ErP | 47-075-96 | NG |
| Duo-tec 28 Combi ErP | 47-075-97 | NG |
| Duo-tec 33 Combi ErP | 47-075-99 | NG |
| Duo-tec 40 Combi ErP | 47-077-03 | NG |
| Duo-tec 28 LPG Combi ErP | 47-075-98 | LPG |
Source: Baxi Duo-tec Combi 24 - 28 - 33 - 40, 28 LPG Installation and Service Manual, 7219665 - 02 (10/15).
Sections: 4.1 Technical data; 10.1 Commissioning the boiler; 10.2 Checking combustion; 10.3 Check the operational (working) gas inlet pressure; 12.1 Annual servicing; 14.1 Setting the gas valve (CO2 check); 17.0 Fault finding (chart I); 17.1 Initial fault finding checks; 18.0 LPG model supplement.
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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.