I'm just looking for some advice. I've just had my 3 port valve replaced. A simple replacement of like for like. The old one had been working fine since I moved into the property 2 years ago but was old and died last week. My local plumber replaced it for me. The new valve isn't automatically sending the hot water to the cylinder. If I manually switch the valve it works fine. From this i have guessed its the wiring. However, when i asked the plumber who fitted it last week to come over and take a look he is refusing to, sayings its an electrical job. Am i expecting too much of him to come and look at his own wiring?