I'm subtenant and I have Vaillant boiler (don't know which model). Every time I use shower after few minutes boiler shuts itself down and the burner lockout indicator is flashing. I'm then without hot water and central heating.

When it shuts down, I start it by pressing the red button. Some times it only provides water to run the central heating.

I've called a repairman and he couldn't solve the problem, he even asked 2 of his colleagues, they couldn't solve the problem either. Here is the picture of boiler and burner lockout indicator:

enter image description here

  • IIUC, sometimes when you restart it, it will start, but only provides heating water, not hot tap water? Have you tried adjusting temperatures to see if lower temps will make a difference (you may not want a shower that cool, but at least would be a clue)? Have you tried turning it off & leaving it off for 30-60 minutes - there may be an internal memory in the controller board that's corrupt and needs to be off for a while to reset itself.
    – FreeMan
    Dec 3, 2020 at 13:57
  • When it stops working flame is extinguished and I don't have central heating nor hot tap water. Then I restart boiler with red button and everything works for a short period of time.
    – Cikson
    Dec 3, 2020 at 15:18

1 Answer 1


I used most the obvious solution: replace whole electronic parts with new ones. I haven't had any problems since then.

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