Glow-worm Ultracom cx combi (24cx, 30cx)
Combi, natural gas (LPG by conversion)
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoFrom the burner % CO₂ tables in section 13 (and 12.9 for LPG). The MI uses the same table for maximum and minimum rate: check the reading against the Check column, and adjust to the Setting column if needed. Section 1 Boiler Specification gives a different NG figure: burner % CO₂ 9.3 nominal, case on and case off, for both sizes. Section 1 gives no LPG figure. |
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CO₂ at low rate More infoHide infoSame table as maximum rate. The MI says adjustment at minimum rate is very coarse: no more than 1/8 of a turn of the offset adjustment at a time, waiting 1 minute between adjustments. |
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Maximum CO | Not given in MI | Not given in MI |
CO/CO₂ ratio More infoHide infoMust not exceed this value. If it does after servicing and adjustment, the MI says the appliance must be disconnected until the ratio is acceptable. | 0.004 | 0.004 |
O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoMeasured at the gas service isolation valve test point with all other gas appliances operating, and the boiler at maximum heat input. The MI says the inlet pressure at the main gas valve can be up to 2 mbar less than the supply pressure at maximum heat input, and that the safe nominal maximum heat input can be achieved at an inlet pressure down to 15 mbar. |
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Gas rate at maximum More infoHide infoApproximate, after 10 minutes from cold, from the gas rates table in 12.5. Section 1 Boiler Specification gives different NG figures, labelled Approximate CH max. gas rate after 10 mins from cold: 24cx 1.94 m³/h, 30cx 2.45 m³/h. The MI doesn’t say which demand the 12.5 table is for. |
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From 0020040955-04 09.09
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 |
|---|---|---|
| Ultracom 24cx | 47-019-06 | NG |
| Ultracom 30cx | 47-019-07 | NG |
Source: Glow-worm Ultracom 24cx, 30cx Installation and Servicing, 0020040955-04 09.09.
Sections: 1 Boiler Specification; 12.4 Initial Lighting; 12.5 Check the Gas Inlet Pressure and Gas Rate; 12.9 LPG Conversion; 13 Servicing: Combustion check and setting the air/gas ratio valve.
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.