Alpha InTec² system (20SE, 30SE)
System boiler, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoMI gives this as CO₂ at maximum CH output, the same for both sizes. Checked in chimney sweep mode with the front case fitted, after the boiler has stabilised. The boiler is supplied set for natural gas; LPG needs the gas type changed in the parameters and a full calibration (MI 5.12, 5.13). | 9.2% ± 0.8 | 10.7% ± 1 |
CO₂ at low rate More infoHide infoMI gives this as CO₂ at minimum output, the same for both sizes. | 9.0% ± 0.8 | 10.0% ± 1 |
Maximum CO More infoHide infoThe LPG table gives no CO figure; it says other technical data is the same as NG data. | 200 ppm | 200 ppm |
CO/CO₂ ratio More infoHide infoMI gives this as maximum CO/CO₂ ratio. The LPG table gives no ratio; it says other technical data is the same as NG data. | 0.003 | 0.003 |
O₂ | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoMI gives this as gas supply pressure, with no range or tolerance. Measurement point not stated in MI. The inlet pressure test point is on the gas valve (MI Fig. 5.2). Section 6 says to check the working gas inlet pressure at maximum rate as described in Section 5.7, but Section 5.7 gives no inlet pressure figure or method. | 20 mbar | 37 mbar |
CO₂ at medium rate (ignition) More infoHide infoMI gives this as CO₂ at medium output (ignition), the same for both sizes. In chimney sweep mode, turn the CH knob until the display shows 78 (20SE) or 49 (30SE). The full calibration sets CO₂ at maximum, medium and minimum. | 9.0% ± 0.8 | 10.6% ± 1 |
Gas rate at maximum More infoHide infoThe LPG table gives no gas rate; it only says other technical data is the same as NG data. |
| Not given in MI |
From Part No. 1.035664 rev. ST.001835/000 (0515/D347)
Enter service mode for high and low rate
High rate
- With no heating or hot water demand and the front case fitted, hold RESET for 8 seconds. The parasol and snowman symbols flash together.
- Turn the central heating knob to maximum. Display shows the output %, up to 99.
- A Climatic controller, if fitted, shows ERR>07. That’s not a fault.
Low rate
- Turn the central heating knob to minimum. Display shows 00.
- For the medium (ignition) check, turn the knob until the display shows 78 (20SE) or 49 (30SE).
Ending the test
- Turn the boiler off (hold the On-Off/Standby button) to cancel. It also ends by itself after 15 minutes.
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| InTec² 20SE | 41-532-28 | NG |
| InTec² 30SE | 41-532-29 | NG |
Source: Alpha InTec² 20SE and 30SE installation and servicing instructions, Part No. 1.035664 rev. ST.001835/000 (0515/D347).
Sections: 2.1 Technical performance data (natural gas and LPG); 5.3 Test for gas tightness and purge the supply; 5.7 Checking the combustion - chimney sweep mode; 5.12 Converting the boiler to operate on LPG; 5.13 CO2 set up procedure; 6 Routine servicing (combustion check).
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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.