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 23 (MI 6.6), boiler at maximum in boost (service) mode. MI 6.5 says to run the boiler at maximum for at least 10 minutes before checking the readings against Table 23. The technical data (MI 2.2, Table 7) gives the same figures without a tolerance. The air/gas ratio valve is factory set and must not be adjusted during commissioning unless the Worcester help line recommends it (MI 5.6). | 9.4 ±0.5% | 10.8 ±0.5% |
CO₂ at low rate More infoHide infoFrom Table 23 (MI 6.6), with the temperature control turned to minimum. The technical data (MI 2.2, Table 7) gives the same figures without a tolerance. |
| 10.4 ±0.5% |
Maximum CO More infoHide infoThe MI gives two limits. The commissioning checks flow chart (MI 5.6, Fig. 59) says CO < 350ppm at maximum and minimum rate. The air/gas ratio steps (MI 6.6) say to check the CO is less than 200ppm at maximum and at minimum. Table 23 itself gives no CO limit. The MI doesn’t say which takes priority. |
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CO/CO₂ ratio More infoHide infoFrom the commissioning checks flow chart (MI 5.6, Fig. 59), at maximum and minimum rate. Table 23 (MI 6.6) gives no ratio. | < 0.004 | < 0.004 |
O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoFrom Figs. 57 and 58 (MI 5.5.1), boiler running at maximum, 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 7) 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 G20 (MI 2.2, Table 7). Table 7 prints the natural gas unit as m²/h, shown as printed; it looks like a misprint for 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 23 instead. Table 7 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), 29.5 kW (440CDi LPG) and 41.5 kW (550CDi). |
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Flue integrity More infoHide infoFrom the commissioning checks flow chart (MI 5.6, Fig. 59), boiler set to maximum rate, analyser zeroed in fresh air. The MI doesn’t say which sample point to use or whether the case should be on: Fig. 65 (MI 6.5) is titled Flue integrity test but shows the flue gas sample point. | O₂ ≥ 20.6% CO₂ < 0.2% | O₂ ≥ 20.6% CO₂ < 0.2% |
From 6 720 815 062 (2015/06)
Enter service mode for high and low rate
High rate
- Hold the boost button (bottom left, below the spanner button) for 10 seconds. It lights steady and the blue power light pulses five times.
- Turn the central heating temperature knob to max for maximum.
Low rate
- Turn the central heating temperature knob to minimum.
- Turn it back to max to return to maximum.
Ending the test
- Hold the boost button for 2 seconds to come out. The blue power light then stays on steady.
- It also ends by itself after 15 minutes.
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| Highflow 440CDi ErP | 47-406-85 | NG |
| Highflow 550CDi ErP | 47-406-87 | NG |
| Highflow 440CDi ErP LPG | 47-406-86 | LPG |
| Highflow 550CDi ErP LPG | 47-406-88 | LPG |
Source: Greenstar Highflow 440CDi ErP & 550CDi ErP floor standing RSF gas fired condensing combination boiler installation, commissioning and servicing instructions, 6 720 815 062 (2015/06).
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; 6.2 Service function; 6.5 Flue gas analysis; 6.6 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.