British Gas British Gas 532/537/542 combi (532, 537, 542)
Combi, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoFrom the CO₂ setting table in Setting the gas/air ratio (MI page 53), boiler at maximum in service mode. CO₂ should be measured 10 minutes after firing. The technical data (MI page 6) 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. |
| 10.8 % ±0.2 |
CO₂ at low rate More infoHide infoFrom the CO₂ setting table (MI page 53), central heating control set to minimum while in service mode. The technical data gives the same figures without a tolerance. |
| 10.5 % ±0.2 |
Maximum CO More infoHide infoFrom Setting the gas/air ratio (MI page 53), checked at maximum. | 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 infoMeasured at the gas valve inlet test point with the boiler running at maximum in service mode, with all other gas appliances working (MI Commissioning, page 36). Setting the gas/air ratio (MI page 53) gives both as minimums: a minimum of 18 mbar for natural gas and 37 mbar for LPG. The MI gives no appliance inlet or meter figure. |
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Gas rate at maximum More infoHide infoMax. 10 minutes from lighting, natural gas figures for G20 (MI Technical data, page 6). Measure at the gas meter after 10 minutes at maximum (MI Commissioning, page 36). In service mode the boiler runs both the central heating and hot water circuits. The technical data gives a central heating max. rated heat input of 30.9 kW for every size, and a hot water max. rated heat input of 32.0, 37.0 and 42.0 kW. |
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From 6 720 612 349a (05.07)
Enter service mode for high and low rate
High rate
- Hold the central heating boost button (below the spanner button) for 10 seconds until it lights up and stays lit.
- Turn the central heating temperature control clockwise to max. The boiler goes to maximum.
Low rate
- Turn the central heating temperature control anticlockwise 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 (MI 5.2 says over a second). 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 |
|---|---|---|
| British Gas 532 | 47-406-02 | NG |
| British Gas 537 | 47-406-04 | NG |
| British Gas 542 | 47-406-06 | NG |
| British Gas 532 LPG | 47-406-03 | LPG |
| British Gas 537 LPG | 47-406-05 | LPG |
| British Gas 542 LPG | 47-406-07 | LPG |
Source: British Gas 532/537/542 wall hung RSF gas-fired condensing combination boiler installation, commissioning and servicing instructions, 6 720 612 349a (05.07).
Sections: Cover (GC numbers); Technical data (page 6); Commissioning (page 36); Setting the gas/air ratio, 5. Setting the CO₂ (page 53); back cover (manufacturer).
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.