Glow-worm cxi combi (24cxi, 30cxi, 38cxi)
Combi, natural gas (30cxi convertible to LPG)
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoCase off (inner casing panel off). With the inner casing panel fitted the MI says readings rise slightly to 9.3% +0.3 −0.5 (MI 12.6); Table 2 gives case on as 9.3% +0.3 −0.5 for 24cxi and 30cxi, and 9.0% +0.3 −0.5 for 38cxi. The MI contradicts itself for the 38cxi: section 12.6 gives 9.1% for all sizes, but Table 2 (MI 1.4) gives 8.8% case off for the 38cxi; Table 2 doesn’t say which rate its figures are for. LPG is the 30cxi only, after conversion (MI 11, LPG conversion step 10): the MI gives this range with the service potentiometer turned fully anti-clockwise to normal running, adjusted with the gas valve throttle if needed. It doesn’t give an LPG figure at a named maximum rate. Max fan speed is selected with the service potentiometer fully clockwise. |
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CO₂ at low rate More infoHide infoCase off. Minimum rate is the service potentiometer at mid-point (3 o’clock), display flashing ‘12’. Same 38cxi contradiction between MI 12.6 and Table 2 as at high rate; Table 2 case on figures are 9.3% +0.3 −0.5 (24cxi, 30cxi) and 9.0% +0.3 −0.5 (38cxi). LPG (30cxi only): the conversion procedure (MI 11, LPG conversion step 9) sets 10.5% ± 0.2% at minimum, while the combustion check (MI 12.6) gives Propane as 10.5% +0.3 −0.7. |
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Maximum CO | Not given in MI | Not given in MI |
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 infoNG: 20 mbar at the boiler (MI 1.3) and at the gas valve inlet pressure test point with the boiler at full rate (MI 11.5). LPG (30cxi only): the MI says ‘appliance supply pressure = 37mbar’ (MI 11, LPG conversion). |
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Gas rate at maximum More infoHide infoApproximate, natural gas, checked at the meter at least 10 minutes after firing (MI 11.5; Table 2 says after 10 minutes from cold). Table 2 minimum gas rates: 24cxi and 30cxi 0.48 m³/h, 38cxi 0.62 m³/h. |
| Not given in MI |
From 0020013349-02.06.05
Enter service mode for high and low rate
High rate
Steps not added yet. Follow the MI.
Low rate
Steps not added yet. Follow the MI.
Ending the test: follow the MI.
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| 24cxi | 47-047-23 | NG |
| 30cxi | 47-047-24 | NG |
| 38cxi | 47-047-27 | NG |
Source: Glow-worm 24cxi, 30cxi, 38cxi High Efficiency Condensing Combination Boilers Instructions for Use, Installation and Servicing, 0020013349-02.06.05.
Sections: 1.3 Gas Supply; 1.4 Technical Data (Table 2); 11 Commissioning, LPG conversion - 30cxi only; 11.5 Testing - Natural Gas only; 12.6 Combustion Check.
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.