if the pessure goes down I have no way of knowing where to turn the pressure up as there is tap under thr boilers as I have seen on others

janet, June 2009

is under the vaillant boiler connect to the cold water pipe and to heating flow pipe

manuel chaves, September 2010

look under the bottom of the boiler at the rear for a silver braided pipe, this is your filler loop ,should also have 2 holes with taps on, if you have NONE of the above.
I reckon the filler loop was removed after boiler was comissioned , also the tap heads were removed before the plastic bottom cover was fitted,to prevent messing, and a guaranteed callback .

wirecutterman, July 2009