I am building a new house and have the cold water pipes running to all my fixtures which are connected to the mains etc.....I also have hot water pipes running to the relevant fixtures, but...my heat pump has not been 'commissioned ' yet, so I at the moment do not have hot water available. I fitted a Thermostatic shower mixer in my bathroom, expecting that at least the cold water would exit from the overhead and hand held shower, but nothing came out at all!....so sorry if this is a stupid question, but will a Thermostatic shower mixer only work if there is both hot and cold water available to it?....or am I way off the mark with that theory....your feedback is greatly appreciated