Glow-worm hxi heat only (12hxi, 15hxi, 18hxi, 24hxi, 30hxi, 38hxi)
Heat only, natural gas (30hxi convertible to LPG)
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoCase off (inner casing panel removed), boiler at maximum (MI 11.6). With the inner casing panel fitted the readings increase slightly: NG 9.3% +0.3 −0.5, LPG 10.7% +0.3 −0.8 (MI 10.5, 11.6). The MI contradicts itself for the 38hxi: sections 10.5 and 11.6 give 9.1% +0.2 −0.5 (case on 9.3% +0.3 −0.5) for every size, but Table 2 (MI 1.4) gives the 38hxi 8.8% +0.2 −0.5 case off and 9.0% +0.3 −0.5 case on. Table 2 doesn’t say which rate its figures are for. LPG is for the 30hxi only, after conversion: MI 10.5 gives the propane figure without saying which rate, and MI 11.6 gives no propane figure at maximum. After converting, the LPG conversion section (step 10) says CO₂ should stay between 9.8% and 10.8% with the boiler back in normal running. |
| 10.5% +0.3 −0.7 |
CO₂ at low rate More infoHide infoCase off, minimum rate (fan at 1200 ±100 rpm, display flashing 12) (MI 11.6). With the inner case front panel fitted the readings increase slightly: NG 9.3% +0.3 −0.5, LPG 10.7% +0.3 −0.8. For the 38hxi, Table 2 (MI 1.4) gives 8.8% +0.2 −0.5 case off and 9.0% +0.3 −0.5 case on, against 9.1% in sections 10.5 and 11.6 (see CO₂ at high rate). LPG is for the 30hxi only: when converting, the LPG conversion section (step 9) says set CO₂ at minimum to 10.5% ± 0.2%. |
| 10.5% +0.3 −0.7 |
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 infoNo tolerance given. MI 1.3 asks for a steady inlet working pressure of 20 mbar (propane 37 mbar) at the boiler. MI 10.5 says check the supply pressure is 20 mb at the inlet pressure test point on the gas valve with the boiler firing at full rate. LPG (30hxi only): the LPG conversion section says the appliance supply pressure should be 37 mbar; no gas valve test point figure is given for LPG. |
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Gas rate at maximum More infoHide infoApproximate, after 10 minutes from cold (Table 2, MI 1.4). The MI contradicts itself for the 24hxi: Table 2 gives 2.58 m³/h, but MI 10.5 gives 2.57 m³/h. MI 10.5 gives 2.0 m³/h for the 18hxi. |
| Not given in MI |
From 0020008153-05 11.05
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 |
|---|---|---|
| 12hxi | 41-047-73 | NG |
| 15hxi | 41-047-74 | NG |
| 18hxi | 41-047-63 | NG |
| 24hxi | 41-047-69 | NG |
| 30hxi | 41-047-64 | NG |
| 38hxi | 41-047-71 | NG |
Source: Glow-worm 12hxi, 15hxi, 18hxi, 24hxi, 30hxi, 38hxi High Efficiency Condensing Boilers: Instructions for Use, Installation and Servicing, 0020008153-05 11.05.
Sections: 1.3 Gas Supply; 1.4 Technical Data (Table 2); 10 Commissioning: LPG Conversion - 30hxi only; 10.5 Testing - Gas; 11.6 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.