Since I started working from home a month ago, I noticed that my boiler kept starting up for a couple of minutes, then stopping.
After a bit of investigation with the manual, I realised that I'd accidentally turned on the Warmstart function (turns the boiler on periodically to allow for quick hot water supply). At a guess, when I last mucked around with the controls when turning the heating on in autumn. I'm in a small flat, i.e. the taps/pipework aren't that far from the boiler, so having this on was a complete waste of gas.
I've taken a meter reading today and while Warmstart has been on, my consumption has doubled! Just thought I'd flag this up for any Vaillant owners who may have done the same thing.
I'm looking forward to getting my next gas bill 