Heating Explained

← All boilers

Vaillant Checked against MI

Vaillant ecoTEC pro combi (VUW GB 246/5-3 A, 286/5-3 A, 286/5-3 A LPG, 306/5-3)

Combi, natural gas and LPG

Combustion figures

FigureNatural 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. Adjust to the front casing removed figure.
Front casing closed
9.2% ± 1.0
Front casing removed
9.0% ± 1.0
Front casing closed
10.4% ± 0.5
Front casing removed
10.2% ± 0.5
CO₂ at low rate
Not given in MINot given in MI
Maximum CO
More infoHide infoCO value with full load. The CO and combustion ratio flowchart in the appendix uses CO less than 350 ppm and CO/CO₂ ratio less than 0.004 at max. and min. rate as its pass level (one box in it prints 335ppm).
≤ 250 ppm≤ 250 ppm
CO/CO₂ ratio
More infoHide infoFrom the full load table in MI 7.11.5. The appendix flowchart uses less than 0.004 at max. and min. 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% ± 1.85.1% ± 0.8
O₂ at low rate
Not given in MINot given in MI
Working inlet pressure
More infoHide infoAt the measuring nipple on the gas valve, boiler at full load (P.01). Technical data gives a nominal gas flow pressure of 20.0 mbar (G20) and 37.0 mbar (G31).
Gas valve test point
13.0–23.0 mbar
Gas valve test point
23.0–43.0 mbar
Gas rate at maximum
More infoHide infoNominal values from the gas flow rate table (MI 7.11.3), measured at the meter after 5 minutes on P.01. Allowed range +5% to −10%: NG 24: 2.74 to 2.35, 28: 3.26 to 2.79, 30: 3.43 to 2.94 m³/h; LPG 24: 2.02 to 1.73, 28: 2.36 to 2.03, 30: 2.52 to 2.16 kg/h. The technical data table gives different G20 figures: 2.5, 2.9 and 3.2 m³/h, and G31 figures of 1.9, 2.2 and 2.4 kg/h.
24
2.61 m³/h
28
3.10 m³/h
30
3.27 m³/h
24
1.92 kg/h
28
2.25 kg/h
30
2.40 kg/h
Flue integrity
More infoHide infoAt the air inlet test point, boiler at maximum rate (appendix flowchart).
O₂ ≥ 20.6%
CO₂ < 0.2%
O₂ ≥ 20.6%
CO₂ < 0.2%

From 0020209589_01 (04.09.2015)

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

ModelGC numberGas
24 (VUW GB 246/5-3 A) ecoTEC pro47-044-54NG
28 (VUW GB 286/5-3 A) ecoTEC pro47-044-55NG
28 (VUW GB 286/5-3 A LPG) ecoTEC pro47-044-56LPG
30 (VUW GB 306/5-3) ecoTEC pro47-044-52NG

Source: ecoTEC pro VUW installation and maintenance instructions, 0020209589_01 (04.09.2015).

Sections: 2.3 Applicability of the instructions; 7.3 Using check programmes; 7.11.2 Checking the leak-tightness of the flue gas system; 7.11.3 Checking the gas flow rate; 7.11.4 Checking the gas flow pressure; 7.11.5 Checking the CO₂ content and adjusting it; F Commissioning checklist (CO and combustion ratio flowchart); J Technical data.

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.