Ball valve has been changed and the iron bend but still overflow problem continues.Last engineer suggested to have a look at cylinder thermostat/boiler thermostat as the o/flow water was initially warm and then becomes cold.When water is used in the bathroom the overflow stops.My boiler is Vokera.The hot water cylinder and cold water tank are in the same place in the loft.Please help as this is driving me crazy

dots, August 2009

It is Possible that the Coil in your HW Cylinder has failed, causing water to migrate from the large Header tank to the smaller F&E tank causing the overflow from the F&E Tank, Make sure that the ball-Vlave is not dripping into the F&E Tank first, otherwise new Cylinder

www.elanar.co.uk, August 2009