by plumbbob »
Sat Oct 04, 2008 5:00 pm
If the cold feed to the bath is 15mm, it suggests it is at high pressure, and shower booster pumps cannot be connected into a mains supply for several reasons. One, but probably not the most important reason, is that normal shower pumps are not designed to withstand the pressure of mains water. The pump bearing water seal and indeed the housing if made of plastic, will very likely fail in time. This also may be the reason the pump won't shut off.
Power mixer showers must have their own dedicated hot supply direct from the hot water cylinder and separate cold water supply from the header tank. Please read the installation manual and ensure the mixer shower has been installed correctly.