hot water not reaching temp ,and rads getting hot when on hw,changed diverter this cured rad problem , but hw same and when hw tap turned off boiler runs on to 86c before shutting down could the ntc cause this as boiler never stays on high flame for long in hw mode?

phil chorley, May 2009

Your DHW plate heatexchanger is has radiater rust build up inside. you need to have it cleaned by removed and chemically cleaned or you can powerflushed the boiler with DHW in it.

Mr K, May 2009