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Worcester Bosch Checked against MI

Worcester Bosch Greenstar 8000 Life regular (GR8300iW 30 R, 35 R, 40 R, 45 R, 50 R)

Regular, natural gas and LPG

Combustion figures

FigureNatural gas (G20)LPG (G31)
CO₂ at high rate
More infoHide infoMeasured 10 minutes after firing, combustion cover on, at the flue gas sample point on the flue turret/adaptor, boiler at maximum in chimney sweep mode.
9.5% ± 0.410.8% ± 0.4
CO₂ at low rate
More infoHide infoMeasured 10 minutes after firing, combustion cover on, boiler at minimum in chimney sweep mode and allowed to settle.
8.6% ± 0.410.2% ± 0.4
Maximum CO
More infoHide infoThe MI gives two limits. Tables 25 and 26 (MI 8.8 and 8.10) give <250 ppm at maximum and <75 ppm at minimum, and 8.10.1 says CO must be <250 ppm. The commissioning flow chart (MI 6.9, Fig. 64) uses CO <350 ppm as the pass limit at both maximum and minimum rate. The MI doesn’t explain the difference.
Max rate
<250 ppm
Min rate
<75 ppm
Flow chart
<350 ppm
Max rate
<250 ppm
Min rate
<75 ppm
Flow chart
<350 ppm
CO/CO₂ ratio
More infoHide infoFrom the commissioning flow chart (MI 6.9, Fig. 64), at maximum and minimum rate. MI 6.7 refers to the technical data for CO/CO₂ ratios, but the technical data doesn’t give any.
< 0.004< 0.004
O₂ at high rate
More infoHide infoNo tolerance given.
4.0%4.6%
O₂ at low rate
More infoHide infoAt minimum rated output. No tolerance given.
5.5%5.5%
Working inlet pressure
More infoHide infoBoiler at maximum in chimney sweep mode. At the meter: NG 19–23 mbar. At the LPG supply: 32–45 mbar. The MI splits the gas valve figure by ≤ 40 kW and > 40 kW without naming models. The model names give heat output in kW (MI 3.5), but the technical data gives the 40 R a maximum heat input of 40.8 kW (output 39.8 kW). The MI text also says the LPG drop from supply to gas valve must not be more than 4 mbar, while Table 15 allows up to 5 mbar for > 40 kW.
Appliance inlet
18–22 mbar
Gas valve test point
16.5–20.5 mbar (≤ 40 kW), 15.5–19.5 mbar (> 40 kW)
Appliance inlet
29.5–42.5 mbar
Gas valve test point
28–41 mbar (≤ 40 kW), 27–40 mbar (> 40 kW)
Gas rate at maximum
More infoHide info10 minutes from lighting. Measure at the gas meter after at least 10 minutes at maximum in chimney sweep mode, with all other gas appliances off. Where there’s no gas meter (e.g. LPG), the MI says check CO/CO₂ instead.
30 R
3.2 m³/h
35 R
3.6 m³/h
40 R
4.3 m³/h
45 R
4.6 m³/h
50 R
5.1 m³/h
30 R
2.3 kg/h
35 R
2.7 kg/h
40 R
3.2 kg/h
45 R
3.4 kg/h
50 R
3.8 kg/h
Flue integrity
More infoHide infoAt the air inlet sample point on the flue turret/adaptor, combustion casing on, boiler at maximum in chimney sweep mode, readings allowed to settle. Readings outside these limits indicate a problem with the flue system or combustion circuit.
O₂ ≥ 20.6%
CO₂ < 0.2%
O₂ ≥ 20.6%
CO₂ < 0.2%

From 6720883866 (2019/04)

Enter service mode for high and low rate

High rate

  1. Hold ok for 5 seconds. When the countdown ends and Chimney sweep shows, press ok.
  2. Confirm the query with Yes.
  3. Use ▲ to set maximum output. It’s accepted after 2 seconds and marked with a tick.

Low rate

  1. Use ▼ to set minimum output. It’s accepted after 2 seconds and marked with a tick.
Ending the test
  • Press ok or ↩ to come out. It goes back to normal by itself after 15 minutes.

Models and GC numbers

ModelGC numberGas
GR8300iW 30 R NG41-406-98NG
GR8300iW 35 R NG41-406-97NG
GR8300iW 40 R NG41-406-96NG
GR8300iW 45 R NG41-406-95NG
GR8300iW 50 R NG41-406-94NG
GR8300iW 30 R LPG41-800-04LPG
GR8300iW 35 R LPG41-800-03LPG
GR8300iW 40 R LPG41-800-02LPG
GR8300iW 45 R LPG41-800-01LPG
GR8300iW 50 R LPG41-406-99LPG

Source: Worcester Greenstar 8000 Life (GR8300iW R) installation and maintenance instructions, 6720883866 (2019/04).

Sections: 3.5 Appliance type overview; 6.4 Chimney sweep mode; 6.6 Checking gas inlet pressure; 6.7 Checking the gas rate; 6.9 CO and combustion check; 6.10 Checking flue integrity; 6.11 Flue gas analysis; 8.8 Flue gas analysis; 8.10 Setting the air/gas ratio; 12.1 Technical data.

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.