Is it just the shower or is it every outlet in the house?
If it's only the shower it's more likely to be a fault with the shower itself - the mixer valves fail.
If it's all outlets, look at the boiler while running a tap - I am guessing this is an older CDi cos Worcester don't make a 45cdi! Does the hot water demand light stay lit when your water goes cold? If you listen to the boiler, does it actually stay lit?
If the demand light goes off when the tap is still running, you have a problem with the diverter or the flow switch.
If it stays on, and the boiler cuts in and out, it's more complex and you may have a sensor fault (amongst other things).
BunSlinger, September 2008
