The overflow pipe from the cold water tank in the loft is constantly dripping.
I had a look, expecting the ball cock to need it's height adjusting or a leaky valve.
In fact, the vent pipe from the immersion tank on the first floor landing is discharging in to the cold water tank at a constant drip. This forces the water level up to and down the overflow pipe.
I do not know how the immersion tank works in detail. Is there a valve that shuts the cold water when the tank is full that may need replacing.
The overflow drips wether the immersion tank is cold, heating or hot.
Can someone please help.