I have never used a combi biasi boiler, and need to know whether all the on/off taps need to be turned before you can use it, I appear to have hot water to the taps and shower without them being turned on
if the taps where of u wouldnt get water out the taps or any water out the hot taps a combi boiler woks like this when u have the heating on it works and when u open a hot water point ie tap or shower the hot water function works stoping the heating and if u have the heating of as soon as u open a hot water point the automatically comes on if its working fine best to leave it alone.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.