Worcester Bosch Checked against MI

Worcester Bosch Greenstar CDi system (30CDi System)

System boiler, natural gas and LPG

Combustion figures

Figure	Natural gas (G20)	LPG (G31)
CO₂ at high rate More infoHide info From the CO₂ setting table in Setting the gas/air ratio (page 49, step 5.3), boiler at maximum output in central heating boost mode with the central heating control at maximum. The MI says CO₂ should be measured 10 minutes after firing the appliance. The table is headed CO₂ setting; the MI gives no separate tolerance for checking an existing appliance. The Technical data (page 6) gives the same figures (CO₂ level at max. rated heat output) without a tolerance. The MI says the combustion is factory set and no adjustment is needed if the gas inlet pressure is correct (Commissioning, page 33, and Finishing commissioning, page 34). The MI doesn’t say whether the case should be on or off. With the optional diverter valve fitted, central heating boost mode runs both the central heating and hot water circuits; on an S or Y plan system, run it in central heating mode only (page 49). Every time the mains supply has been interrupted, the boiler runs for 15 minutes at minimum heating output to fill the condensate trap (Starting the appliance, page 31).	9.6% ±0.2	11.5% ±0.2
CO₂ at low rate More infoHide info From the same CO₂ setting table (page 49), with the central heating control turned to minimum while in central heating boost mode (steps 5.4 and 5.5). The Technical data (page 6) gives the same figures (CO₂ level at min. rated heat output) without a tolerance.	9.0% ±0.2	10.5% ±0.2
Maximum CO More infoHide info From Setting the gas/air ratio (page 49): Check CO is less than 200 ppm, with the boiler at maximum straight after setting the CO₂ (step 5.3). The MI gives no CO limit at minimum rate and no CO check in the Commissioning section.	less than 200 ppm	less than 200 ppm
CO/CO₂ ratio	Not given in MI	Not given in MI
O₂	Not given in MI	Not given in MI
Working inlet pressure More infoHide info From Commissioning, Measuring the inlet pressure (page 33): manometer on the inlet pressure test point (inlet test nipple on the gas valve), boiler running at maximum in central heating boost mode, with all other gas appliances working. The MI prints N.G. minimum 18 mbar and L.P.G. 37 mbar. Setting the gas/air ratio (page 49, step 5.3) repeats them as a minimum of 18 mbar for natural gas and 37 mbar for LPG. The MI gives no maximum, no appliance inlet figure and no meter or regulator figure. Mains supplies (page 10) says NG boilers must be connected to a governed meter and LPG boilers to a regulator. Don’t continue commissioning until the correct gas inlet pressure is achieved (page 33).	Gas valve test point minimum 18 mbar	Gas valve test point 37 mbar
Gas rate at maximum More infoHide info From the Technical data (page 6), Gas flow rate - Max. 10 minutes from lighting: Natural Gas G20 and Propane Gas (LPG). Commissioning (page 33) says to measure the gas rate at the gas meter after 10 minutes operation at maximum. The Technical data gives a max. rated heat input of 30.9 kW for both NG and LPG, and a min. heat input of 8.0 kW (NG) and 11.5 kW (LPG).	3.2 m³/h	2.4 kg/h

From 6 720 612 453b (2006/01)

Enter service mode for high and low rate

High rate

Hold the central heating boost button for 10 seconds until it lights up and stays lit.
Turn the central heating temperature control to max. The boiler goes to maximum.

Low rate

Turn the central heating temperature control to minimum. The boiler goes to minimum.
Turn it back to max to return to maximum.

Ending the test

Hold the central heating boost button for 2 seconds. Its light goes out and the blue power light stays on.
It also ends by itself after 15 minutes.

Models and GC numbers

Model	GC number	Gas
30CDi System	41-311-93	NG
30CDi System LPG	41-311-97	LPG

Source: Worcester Greenstar 30CDi System wall hung RSF gas-fired condensing boiler instruction manual: installation, commissioning and servicing, 6 720 612 453b (2006/01).

Sections: Cover (GC numbers); Technical data, page 6; Mains supplies, Gas supply, page 10; Starting the appliance, page 31; Commissioning, Setting the boiler to maximum and Measuring the inlet pressure, page 33; Finishing commissioning, page 34; Inspection and service, Setting Boiler to Maximum, page 37; Setting the gas/air ratio, 5. Setting the CO₂, page 49.

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.