It seems that when turning on the Hot Water Taps the boiler fires up and displays 'd' which is correct for the taps but the radiators become really hot and the water from the taps becomes luke warm. sometimes the tap water will go cold but the boiler is still running. Any Ideas?
Yes, your diverter valve is stuck or getting stuck in mid position allowing the hot water called for by the tap to flow into the ch system at the same time.
