Thanks Dave, you have confirmed my suspicions and no it doesn't happen when HW only is on. Now trying to locate indirect cylinder with imperial dimensions between the primaries i.e. a straight swap if I'm lucky.
My problem is the F & E tank overflows when the heating is turned on. The system is a floor mounted Potterton gas boiler situated downstairs with an indirect cylinder situated upstairs. It is gravity feed with no motorised valves. The cold water supply tank with the F & E tank are situated i...
