Vaillant ecoTEC plus open vent (412, 415, 418, 424, 430, 435; VU ..6/6-5 OVZ)
Heat only (open vent), natural gas
Combustion figures
| Figure | Natural gas (G20) |
|---|---|
CO₂ at high rate More infoHide infoMeasured at the flue gas analysis point on check programme P.01 (maximum load), after waiting 5 minutes for a stable reading. Both tables say front casing on or off. At commissioning (MI 7.11.3), a value outside 9.2 ±1 % means don’t start up the boiler and inform Customer Service. At a service (MI 11.3 and 11.4), a value outside 9.2 ±1 % is set to CO₂ at full load 9.2 ±0.2 %, read with the front casing removed. |
|
CO₂ at low rate | Not given in MI |
Maximum CO More infoHide infoFull load figure from the Setting the CO₂ value table (MI 11.4). The Benchmark CO and combustion ratio flowchart in Appendix I (MI p. 42) uses CO less than 350 ppm at max and min rate, but less than 335 ppm in its re-check box after checking the seals. The MI doesn’t say which limit takes priority. |
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CO/CO₂ ratio More infoHide infoThe MI table (MI 11.4) labels this row just CO/CO₂, under the full load rows, and the check is done on P.01 (maximum load). The Benchmark flowchart in Appendix I (MI p. 42) uses a ratio less than 0.004 at max and min rate. The MI doesn’t say which limit takes priority. |
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O₂ at high rate More infoHide infoO₂ at full load, from the Setting the CO₂ value table (MI 11.4), front casing on or off. | 4.5 ±1.8 vol. % |
O₂ at low rate | Not given in MI |
Working inlet pressure More infoHide infoPermissible connection pressure, measured at the test nipple on the gas isolator cock with the boiler at full load (check programme P.01, or P.03 without eBUS control) and all other gas appliances in the property working. The MI also gives it as 1.7–2.0 kPa. The technical data gives the G20 gas supply pressure as 2.0 kPa (20.0 mbar). If it’s outside the range, don’t make any adjustments and don’t start up the boiler. |
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Gas rate at maximum More infoHide infoNominal gas rate, with the permitted range (−10% to +5%) in brackets, from the gas flow rate table in MI 7.10. That table lists rates against Qnw from the data plate; they’re matched to sizes here using the hot water maximum heat input in the technical data (412, 415: 18.4 kW; 418: 25.7 kW; 424: 30.6 kW; 430, 435: 35.7 kW). Measured at the gas meter on check programme P.01 with the front casing on, after at least 5 minutes, with all other gas appliances off. The technical data also gives gas flow at P max. (G20) in heating mode as 412: 1.3, 415: 1.6, 418: 1.9, 424: 2.6, 430: 3.2, 435: 3.8 m³/h, and in hot water mode as 412: 1.9, 415: 1.9, 418: 2.7, 424: 3.2, 430: 3.8, 435: 3.8 m³/h. The MI doesn’t say whether P.01 runs at the heating or hot water maximum. |
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Flue integrity More infoHide infoAt the air inlet (supply air) test point, boiler at maximum rate, from the Benchmark flowchart in Appendix I (MI p. 42). MI 7.11.2 says that if any CO or CO₂ is found in the supply air, search for the leak in the flue or for flue gas recirculation. Appendix A says products with a rear air/flue connection can only have the combustion analysis done with the casing removed, and don’t need testing for flue gas recirculation. | O₂ ≥ 20.6% CO₂ < 0.2% |
From 0020238195_05 (06.06.2018)
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 |
|---|---|---|
| ecoTEC plus 412, VU 126/6-5 OVZ (H-GB) | 41-694-13 | NG |
| ecoTEC plus 415, VU 156/6-5 OVZ (H-GB) | 41-694-14 | NG |
| ecoTEC plus 418, VU 186/6-5 OVZ (H-GB) | 41-694-15 | NG |
| ecoTEC plus 424, VU 246/6-5 OVZ (H-GB) | 41-694-16 | NG |
| ecoTEC plus 430, VU 306/6-5 OVZ (H-GB) | 41-694-17 | NG |
| ecoTEC plus 435, VU 356/6-5 OVZ (H-GB) | 41-044-76 | NG |
Source: Vaillant ecoTEC plus VU ..6/6-5 OVZ (H-GB) installation and maintenance instructions, 0020238195_05 (06.06.2018).
Sections: 2.3 Validity of the instructions; 7.5 Checking the factory setting; 7.10 Checking the gas flow rate; 7.11.1 Checking the gas connection pressure (gas flow pressure); 7.11.2 Checking the leak-tightness of the flue gas installation and flue gas recirculation; 7.11.3 Checking the CO₂ content; 11.3 Checking the CO₂ content; 11.4 Setting the CO₂ content; Appendix A Inspection and maintenance work; Appendix B Installer level – Overview; Appendix I Commissioning Checklist; Appendix J Technical data.
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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.