leaking overflow pipe & running the hot water tap to sto

[laupsek]

Hello,
I have a problem with an overflow pipe that juts out from the first floor of my 3 bedroom house. Most days now for the last few weeks, there is a steady stream of water emerging from this pipe onto the roof of our lean-to immediately below; always it seems, in the early hours of the morning. It's not just the noise which is disconcerting but the fact that so much water is being wasted and was wondering if anyone had any suggestions.
Flushing the toilet and running the cold water taps haven't made any difference to the rate of flow from the pipe. However, I have discovered that if I run the hot water tap for just a few minutes then the stream of water from the pipe soon stops. What is happening and how can I prevent the water from overflowing?

 

[doitall]

Fit a new ballvalve by the sound of it.

The pressure is higher at night, plus you are not using water, so the storage tank is overflowing, running the hot water drops the level to below the overflow pipe.

 

[John506]

I would get up there whilst you can hear the noise, see what's going on in the tank, you will see the problem straight away.