When a plumber was replacing my CW cistern he noticed that the heating feed/expansion cistern drained and reported that I have a leak in my heating system. He said the leak was so bad that it is definitely downstairs as otherwise there would be obvious damage to the ceiling below.
I have looked all over for the leak, the only place left to check is under two expensive floors (the floors are raised on joists about 50cm above the ground). Before I start damaging expensive floor boards, is there any other possibility?
One thing that springs to mind is that the HW cylinder could be leaking water internally (i.e. leaking hot water from the coil into the tank). Does this sort of thing happen much or am I just graping at straws?
Any advice much appreciated! Chris.