Setting High and Low combustion rates on Vaillant gas boilers

Set High and Low combustion rate on ecoTEC pro

Vaillant ecoTEC pro control panel drawing
1, information screen; 2, current assignment of right selection button; 3, left and right selection buttons; 4, plus and minus buttons; 5, maximum output operation for engineers; 6, access to additional info menu; 7, current assignment of left selection button; 8, active operating status

To enter Installer level

The boiler we worked on was a Vaillant ecoTEC pro 28 H VUW GB 286/5-3 A R4 (G.C. No. 47-044-89) but this also applies to the ecoTEC pro 24 H VUW GB 246/5-3 (G.C. No. 47-044-88) and the ecoTEC pro 28 P VUW GB 286/5-3 (G.C. No. 47-044-90)

To enter Installer level, press both the i buttons (left and right selection buttons) together. You may need to press them twice if the display is not lit. The first press seems to wake up the display.
An S code will display.

Press the right i (selection) button to get Code to display (if the light went out, it will take 2 presses).
Use + and buttons to select code 17 (installer code) and press right i button to confirm.
Now, pressing the right i button toggles between D (diagnostic codes), P (program codes) and F (fault codes).

Setting high and low combustion rates

When P. shows with two hyphens flashing, use + and to select the code you want (e.g. P.02 is low combustion rate).
Press the right i button to confirm.

Pressing the left i button goes back one step.
With the boiler running P.02, pressing left i button will show P.02 where 02 is flashing.
Use + or buttons to select P.01 and confirm it with the right i button.
P.01 is the high combustion rate.

To return boiler to normal operation

When combustion tests are complete, press left i button.
P. will be shown with the code number flashing.
Remember, if the screen has gone dark it will take an extra press to wake it up.
Press left i button again and P. will show with two flashing hyphens.
Press left i button again to return to normal boiler operation.

A note about Vaillant and Chimney Sweeps

The Vaillant ecoTEC pro Operating Instructions have a note about chimney sweeps. For Item 5 of the drawing above, their label says, “Maximum output operation (for chimney sweeps only)“. The drawing shows a picture of a chimney sweep’s hat and ladder.
This may seem strange in the UK but makes sense in Germany, and Vaillant is a German manufacturer.

German cities have many old buildings with complex flue systems. Some of them are shared flue systems. In Germany, boiler flue installation and inspection, and combustion analysis, are carried out by chimney sweeps and not by central heating installers.
Other German manufacturers have chimney sweep symbols on some of their older UK boilers but these symbols are less common now.