Hi there, the problem that I have is that when the kitchen hot tap is turned on the flow from the bathroom hot taps dries up completely. the hot water is supplied from a year old vaillant turbo max combi housed in a bedroom airing cupboard. I want to fit a thermostatic mixer shower to replace my existing electric one but I'm worried about what will happen if I'm in the shower and the downstairs tap gets switched on. Any advice much appreciated.