Hot water being back flowing into Cold water tank

[alan999]

If your cold water tank is backfilling the water must somehow be coming from the cold water main.
It could be directly through a mixer tap or shower in which case you would hear water running through the pipework even if all the taps were turned off.
It could also be indirectly by central heating water getting into the hot water inside the hot water cylinder. In this case I would expect the cold water pipe to the feed and expansion tank to keep topping the central heating water up. If nothing is happening inside the feed and expansion tank the central heating water cant really be escaping.
I would try to isolate the mixer taps and showers and then see if the problem persists.

 

[Chris Dodds]

Cheers mark, both tanks are at the same level, it seems not as bad as I have turned the temp does on the tank.

I have my utilities company coming round to sign me up to their central heating cover plan so hopfully may be able to get sorted though that

 

[gassymark]

Ok best of luck let us know the out come

 

[Chris Dodds]

Thanks alan but when I saw looked two days ago it was deffo filling from the pipe that feeds the hot water tank and other devices