Worcester Bosch Greenstar Highflow CDi ErP combi (440CDi, 550CDi)
Floor standing combi, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoFrom Table 15 (MI 6.8). The CO₂ should be measured after 10 minutes, with the combustion chamber cover on, boiler at maximum in service mode. The technical data (MI 2.2, Table 6) gives the same figures without a tolerance. | 9.4 ± 0.2% | 10.8 ± 0.2% |
CO₂ at low rate More infoHide infoFrom Table 15 (MI 6.8), temperature control turned to minimum and output allowed to settle for about 10 minutes. The technical data (MI 2.2, Table 6) gives the same figures without a tolerance. |
| 10.4 ±0.2% |
Maximum CO More infoHide infoThe MI gives two limits. Table 15 and the air/gas ratio steps (MI 6.8) say CO less than 200 ppm at maximum and minimum. The commissioning checks flow chart (MI 5.6, Fig. 41) uses CO < 350ppm at both maximum and minimum rate. The MI doesn’t say which takes priority. |
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CO/CO₂ ratio More infoHide infoThe MI gives two limits. Table 15 (MI 6.8) gives 0.002 in brackets after the CO limit: CO - less than 200 ppm (0.002 ratio). The commissioning checks flow chart (MI 5.6, Fig. 41) says CO/CO₂ ratio < 0.004 at maximum and minimum rate. |
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O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoFrom Figs. 39 and 40 (MI 5.5.1), boiler running at maximum in service mode, with all other gas appliances working. At the meter: NG 19–23 mbar. At the regulator: LPG 32–45 mbar. The pressure at the boiler must not be less than the meter pressure minus 1 mbar (NG) or 2.5 mbar (LPG), and the drop from the meter to the gas valve must be no more than 2.5 mbar (NG) or 4 mbar (LPG). The technical data (MI 2.2, Table 6) gives a gas supply pressure of 20 mb for G20 and 37 mb for G31. |
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Gas rate at maximum More infoHide infoMax. 10 minutes from lighting, natural gas (network gas) at an assumed CV of 38.76 MJ/m³ (MI 2.2, Table 6). With G20 test gas the table gives 3.27 and 4.4 m³/h. Measure at the gas meter after 10 minutes at maximum (MI 5.5.2). Where there’s no gas meter (e.g. LPG), check CO/CO₂ against Table 15 instead. Table 6 gives a central heating max. rated heat input of 29.6 kW (440CDi) and 31 kW (550CDi), and a hot water max. rated heat input of 29.6 kW (440CDi, NG) and 41.5 kW (550CDi). |
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Flue integrity More infoHide infoAt the combustion air sample point at the top left of the combustion chamber, combustion cover fitted, boiler running at maximum for at least 10 minutes, readings allowed to stabilise (MI 6.5). Readings outside these limits could mean a problem with the flue system or combustion circuit. | O₂ ≥ 20.6% CO₂ < 0.2% | O₂ ≥ 20.6% CO₂ < 0.2% |
From 6 720 818 077 (2016/04)
Enter service mode for high and low rate
High rate
- Hold the Service engineer button for 10 seconds. It lights up continuously and the blue power light pulses five times.
- Turn the central heating temperature control to maximum. The boiler goes to maximum.
Low rate
- Turn the central heating temperature control to minimum. The boiler goes to minimum.
- Turn it back to maximum to return to maximum.
Ending the test
- Press the Service engineer button again. MI differs: over 1 second (p. 36) or hold 2 seconds (p. 37). Blue power light then stays on.
- It also ends by itself after 15 minutes.
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| Highflow 440CDi ErP | 47-406-89 | NG |
| Highflow 550CDi ErP | 47-406-91 | NG |
| Highflow 440CDi ErP LPG | 47-406-90 | LPG |
| Highflow 550CDi ErP LPG | 47-406-92 | LPG |
Source: Greenstar Highflow 440CDi ErP and 550CDi ErP floor standing RSF gas fired condensing combination boiler installation, commissioning and servicing instructions, 6 720 818 077 (2016/04).
Sections: Cover (GC numbers); 2.2 Technical data; 5.5 Checking gas inlet pressure; 5.5.1 Measuring the inlet pressure; 5.5.2 Checking the gas rate; 5.6 CO and combustion check; 6.5 Checking the flue integrity; 6.6 Flue gas analysis; 6.8 Setting the air/gas ratio.
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.