UK Plumber Forum

[Peter limbert]

Hi, hopefully some can help me with this frustrating problem.
My Cold water loft tank is overflowing intermittently and only stops when I draw hot water from taps, showers etc.
How is the back flow of water into the tank happening. Some things I have done so far..
New ball valve fitted and working.
Brand new hot water cylinder fitted by a plumber.
Help !!!
Peter

[SimonG]

Do you have any mixer taps or a mixer shower with no double check valves? And the cold from mains supply?

[REDSAW]

oh no, not the 'you need a new cylinder' jobbie!