I have a Worcester 240 gas boiler. Recently, I've noticed that if a hot water tap is partially opened there is plenty of hot water. However, when the tap is opened fully the temperature gradually reduces to not much more than stone cold. This has become a problem with the shower (Aqualisa Axis mixer type) as it now doesn't reach a temeperature where it can be used without grimacing!! I've watched the flame inside the boiler and it doesn't seem to take account of how much water is flowing through it. As soon as there is demand, the main burner kicks in to a level. The flame remains at that initial level regardless of changes to flow. Should the flame adjust to match the demand? If so what might be causing it to fail?

Neil (North Wales, UK), January 2009

Neil I have exactly the same problem with my 240 - Did you fix it m8 ? If so what was it please.
Pondskater(at)virgin(.)net

rob, August 2009

could be to much pressure coming in to boiler from cold water mains inlet try fitting a pressure reducing valve to cold water inlet just before boiler

danny, March 2009

could be modulating coil on gas valve/ insufficint gas /hw plated heat exchanger may be blocked

steve (east sussex), February 2009