Worcester Bosch Greenstar CDi Classic combi (29CDi, 34CDi, 38CDi, 42CDi)
Combi, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoFrom Table 10 (MI 6.2), measured 10 minutes after firing, boiler at maximum in performance test mode. The ±0.4% tolerance is for checking an existing appliance. After cleaning or replacing parts, or when adjusting because the reading is outside that tolerance, the tolerance is ± 0.2%. The technical data (MI 2.3, Table 5) gives the same figures without a tolerance. The MI says combustion is factory set and no adjustment is needed if the gas inlet pressure is correct (MI 5.5). |
| 11.5% ±0.4 |
CO₂ at low rate More infoHide infoFrom Table 10 (MI 6.2), with the central heating control turned to minimum while in performance test mode. Same tolerance rules as at high rate. The technical data (MI 2.3, Table 5) gives the same figures without a tolerance. |
| 10.5% ±0.4 |
Maximum CO More infoHide infoFrom Table 10 and the air/gas ratio steps (MI 6.2). | less than 200 ppm | less than 200 ppm |
CO/CO₂ ratio More infoHide infoTable 10 (MI 6.2) gives 0.002 in brackets after the CO limit: CO - less than 200 ppm (0.002 ratio). | 0.002 | 0.002 |
O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoFrom Figs. 41 and 42 (MI 5.5.1), boiler running at maximum in performance test 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 or regulator to the gas valve must be no more than 2.5 mbar (NG) or 4 mbar (LPG). |
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Gas rate at maximum More infoHide infoMax. 10 minutes from lighting, natural gas figures for G20 (MI 2.3, Table 5). Measure at the gas meter after 10 minutes at maximum in performance test mode (MI 5.5.2). Where there’s no gas meter (e.g. LPG), check CO/CO₂ against Table 10 instead (MI 6.2). Performance test mode runs the central heating circuit only (MI 5.5), and Table 5 gives a central heating max. rated heat input of 30.9 kW for every size (hot water: 30.9, 35.0, 40.0 and 42.0 kW). |
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From 6 720 803 599 (2012/08)
Enter service mode for high and low rate
High rate
- Hold the Performance test button for 10 seconds until it stays lit. Display alternates three bars on each digit with the flow temperature.
- Turn the central heating control to maximum. The boiler goes to maximum.
Low rate
- Turn the central heating control to minimum. The boiler goes to minimum.
- Turn the central heating control back to maximum to return to maximum.
Ending the test
- Press the Performance test button again; its light goes out. MI differs: press for over a second, or hold for 2 seconds.
- It ends by itself after 15 minutes.
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| 29CDi Classic | 47-406-34 | NG |
| 34CDi Classic | 47-406-36 | NG |
| 38CDi Classic | 47-406-38 | NG |
| 42CDi Classic | 47-406-10 | NG |
| 29CDi Classic LPG | 47-406-35 | LPG |
| 34CDi Classic LPG | 47-406-37 | LPG |
| 38CDi Classic LPG | 47-406-39 | LPG |
| 42CDi Classic LPG | 47-406-11 | LPG |
Source: Greenstar CDi Classic wall hung RSF gas fired condensing combination boiler installation, commissioning and servicing instructions, 6 720 803 599 (2012/08).
Sections: Cover (GC numbers); 2.3 Technical data; 5.5 Commissioning; 5.5.1 Checking the gas inlet pressure; 5.5.2 Checking the gas rate; 6.2 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.