Hi crackers 1978 There are a lot of questions that would need answering, even then it would be difficult to provide a solution remotely. How does the system operate, is the shower fed directly from the boiler; are there pressure/flow valves in the system; is the existing shower valve thermostatic; are there isolating valves on the shower valve and are they open....etc.......... Suggest you get your installer back to sort out this issue. Regards S
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!