Static overlay

Energy bills have been increasing. There are still ways to reduce this.

Vaillant Boiler Symbols

Shown below are the symbols and meanings for the newer generation of Vaillant boilers as well as some older models. These symbols are mostly found on the ecotec series of boilers. If anything is not clear, please feel free to let us know.

MBNoSymbolDescription and ExplanationModels Applicable to:
1vaillant flame symbolFlame: Permanently on: Correct burner operation; Burner on
New Ecotec
2vaillant boiler symbol - bar graphDisplay of the current burner modulation rate (bar graph display)The bar graph will go up and down depending on the power level the boiler is firing at. New EcotecArticle
3Flame: Permanently on: Correct burner operation; Burner on
Older Ecotec
4Flame with cross:
Boiler is at lock out and will display fault code
Older EcotecArticle
5Display of the current filling pressure of the heating system (bar graph display).
The filling pressure must be in the mid range between the two dotted lines.
- Permanently on: The filling pressure is within the permitted range.
- Flashing: The filling pressure is outside of the permitted range
6Heating mode active- Permanently on: Heat demand, heating mode
6.1Heating mode active- Flashing: Burner on in heating mode
7Hot water generation active- Permanently on: In draw-off mode before burner is on
- Flashing: Burner on in draw-off mode
7.1Hot water generation active- Flashing: Burner on in draw-off modeArticle
8Hot water generation active For VUI (Storage Combination) / VUW (Combination) boilers:

- Permanently on, burner is on: In draw-off mode before the

8.1Hot water generation active - Flashing: Burner on in draw-off modeArticle
9Hot water generation active On VU (System / OpenVent) boilers:

- Permanently on:time slot activated for hot water generation
9.1Hot water generation active - Flashing: Domestic hot water cylinder is being heated, burner onArticle
10Maintenance / Service required.In the "Live monitor", you can read further information about the reason for the service (¬ Section 8.2).Article
11Summer mode active Heating mode is switched offDecrease the heating flow temp until it says off. Increase the flow temp to original value to turn heating back on.Article / Video
12Boiler anti-cycling time is active
This function is used to prevent frequent on/off operations, and therefore contributes to prolonging the life of your boiler.
The symbol also appears if the boiler is in a waiting period.
13 Internal pump is running
14vaillant gas valve symbolGas valve is activated

Fault in the boiler.
Appears instead of the basic dis-play (¬ Section 4.4).
A plain text display explains the displayed fault code.
Example: F.10 Flow NTC short circuit.
Article / Page
A green transition that works for you.

Save up to £400 a year on your heating bill with a hybrid heat pump from Econic Energy

Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.