DIY Doctor UK DIY Forums

I have an old cottage with simple coalfired back boiler which heats hot water cylinder, no radiators.
Problem is overflow from hot cylinder into overflow/topup tank, even when fire not on.
Last night fire was out approx 11pm, water was hot but level in overflow tank was ok. This morning approx 7am water from tap was lukewarm. This afternoon, fire still not on, there is a steady dribble pouring from overflow outside onto pavement. Water inlet valve to system shut off all day so excess isn't coming from mains supply.
Any ideas?

Hi RED1

If your F+E tank has it's water level lower than that in main storage tank, I would think it likely that there is an internal leak in the cylinder primary coil.