how can i fix a vailliant combi boiler with fault F.28?

I have the same problem ! If you lift down the front panel, there is a reset button ( with a flame sign on it) which you need to press. This may get the boler going again. But in the long run, it probably means there is a fault with the contol board, which is creating a weak spark to ignite the gas.

mick
April 2006