[Katana666]

Hi, I have 2 water tanks in my loft for an indirect system-1 large cold water storage and 1 much smaller tank, which I am given to understand serves water expansion from the radiators.
The ballcock valve is heavily corroded and was allowing water to continually enter the tank, resulting in a persistent overflow to the out pipe sending water into the garden. As a temporary solution, I have placed a section of wood across the top of this tank and tied the ball cock arm off to it, thereby force shutting the valve and preventing any water enering the tank-additionally then bailing the tank to below the overflow line, meaning no water in or out.
The heating will soon want to go back on for the winter months, and I have been told that though this tank is currently not in operation I shouldn't worry about it negatively effecting the hot water system expansion.
Naturally the appropriate parts will want to be replaced sooner than later, but should that not happen immediately, and the heating is back on, will there be an immediate need for concern?