HELP! Tank keeps filling up!

[delboy19]

Update

Fitted the single check valve on the mixer tap downstairs (hot pipe) and problem still persists.

Think it's time to get someone in.......

 

[seco services]

have you not got any isolation valves on the mixers ?
makes life easier to find which one.

 

[delboy19]

I'll try that. If I can find out which mixer is the problem, will it still be a case of fitting a check valve?

Last throw of the dice. Will post update tomorrow.

Thanks

ps water from overflow is warm water

 

[seco services]

If I can find out which mixer is the problem, will it still be a case of fitting a check valve?

yes or change mixer.

ps water from overflow is warm water

it will be as the cold is pushing the hot back.

 

[delboy19]

Isolated both the shower mixer and the bath tap one at a time, shower first. Definitely an improvement. Still a slow drip from overflow.

Then isolated the bath tap. No change to overflow. Still slowly dripping.