Vaillant ecoTEC plus VUW ../5-5 combi (825, 832, 835, 838)
Combi, natural gas and LPG
Combustion figures
| Figure | Natural gas (G20) | LPG (G31) |
|---|---|---|
CO₂ at high rate More infoHide infoAfter 5 minutes in full load mode (check programme P.01), measured at the flue gas analysis point. When adjusting, set the case-removed value. |
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CO₂ at low rate More infoHide infoThe MI gives CO₂ at full load only. | Not given in MI | Not given in MI |
Maximum CO More infoHide infoAt full load. The Benchmark flowchart printed in the MI (MI p. 61) uses CO less than 350 ppm at maximum and minimum rate (one box on it says 335 ppm). | ≤ 250 ppm | ≤ 250 ppm |
CO/CO₂ ratio More infoHide infoAt full load. The Benchmark flowchart printed in the MI (MI p. 61) uses a ratio less than 0.004 at maximum and minimum rate. | ≤ 0.0031 | ≤ 0.0026 |
O₂ at high rate More infoHide infoAfter 5 minutes in full load mode with the front casing closed. | 4.5% ± 1.8 | 5.1% ± 0.8 |
O₂ at low rate | Not given in MI | Not given in MI |
Working inlet pressure More infoHide infoMeasured at the measuring nipple (lower screw) on the gas valve, boiler at full load in check programme P.01. Nominal flow pressure in the technical data: NG 20.0 mbar, LPG 37.0 mbar. |
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Gas rate at maximum More infoHide infoNominal rate at the gas meter, with the permitted range (−10% to +5%) in brackets. Check after at least 5 minutes in check programme P.01 with the front casing fitted and all other gas appliances off. The MI lists these by nominal heat output (25, 32, 35, 38 kW, BS EN 483), not by model. The technical data (MI p. 64, based on hot water generation) gives rounded figures: NG 825 2.7, 832 3.4, 835 3.8, 838 4.2 m³/h; LPG 825 2.0, 832 2.5, 835 2.8, 838 3.1 kg/h. |
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Flue integrity More infoHide infoAt the air inlet test point with the boiler at maximum rate (Benchmark flowchart, MI p. 61). | O₂ ≥ 20.6% CO₂ < 0.2% | O₂ ≥ 20.6% CO₂ < 0.2% |
From 0020209591_00 (21.05.2015)
Enter service mode for high and low rate
High rate
Low rate
Models and GC numbers
| Model | GC number | Gas |
|---|---|---|
| 825 (VUW GB 256/5-5) | 47-044-57 | NG |
| 832 (VUW GB 326/5-5) | 47-044-58 | NG |
| 832 (VUW GB 326/5-5 LPG) | 47-044-59 | LPG |
| 835 (VUW GB 356/5-5) | 47-044-53 | NG |
| 838 (VUW GB 386/5-5) | 47-044-60 | NG |
Source: Vaillant ecoTEC plus VU, VUW installation and maintenance instructions, 0020209591_00 (21.05.2015).
Sections: 2.3 Applicability of the instructions; 7.7 Using check programmes; 7.15.2 Checking the leak-tightness of the flue gas system and for flue gas recirculation; 7.15.3 Checking the gas flow rate; 7.15.4 Checking the gas flow pressure; 7.15.5 Checking the CO₂ content and, if necessary, adjusting it (air index setting); G Commissioning checklist; K 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.