Attic Overflow Comes and Goes?

SickCert

Hello guys.
A neighbour claimed to have heard my tank filling early this morning and on several mornings i have noticed a pool of water on the garden floor. On checking the tank and playing with the ballcock for some time watching it rise and fall, i know its not the problem. It stops 1/8in below the outpipe.
There is another pipe going into the top of the tank which i believe is a heating vent? Which comes up from the hot tank in the kitchen. Is it possible for water to travel upwards to the tank and what causes this?

Thanks.

GreeBo

Does your heating or immersion come on for long in the mornings?
it might be overflowing the cylinder (as the water gets hotter it expands) and overflowing outside...

SickCert

Every morning, the wife leaves it on for sometime.

crosstownk

I'd say GreeBo is right. The hot water is expanding and venting, which is filling your attic tank a little bit more. Try adjust the ball cock on the attic filler tap so it stops filling with the water level further from the overflow pipe.

SickCert

The only adjustments to make seem to be the end metal piece, just twist?

Zaph

I had that problem last year. Got a guy to look at it and he replaced the ballcock because it had rusted at one spot and as a result it wasn't always rising and falling as it should. Everything works fine now.

SickCert

Guy ive got a result and reduced the tank level by an inch, by supporting the mains pipe with a piece of timber ive removed the weight and the water shuts off much sooner. Piccy below!

Wishbone Ash

SickCert wrote:

The only adjustments to make seem to be the end metal piece, just twist?

You could also bend the end of the arm of the ballcock down a bit making the flow stop a bit sooner.

parsi

Wishbone Ash wrote:

You could also bend the end of the arm of the ballcock down a bit making the flow stop a bit sooner.

There is also the possibility of the washer in the ball valve being worn. This happened to me and the dribble out was only noticeable in the early mornings (or if you'd been away for a while) when there hadn't been a spate of flushing etc. I tried bending the arm (no luck), using additional floats (no luck) so had to bite teh bullet and replace the valve.

Dilbert75

Replacing ballcocks on a regular basis is a good idea anyway. In fact I had a recent personal experience with a dodgy ballcock valve - one of the water tanks in work, supplies fire hoses, sits at high level over the boiler. Over the bank holiday weekend (wouldn't you know it) the ball broke off the valve and floated on top of the water. Valve opened fully and, as it was for fire hoses, the mains supply was unrestricted. So much so that the overflow from the tank couldn't take it away as fast as it was being supplied. Tank overflowed, flooded half of factory, burnt out controller on boiler, no heat for 3 days (coldest days for months too). Bad enough in a factory but imagine your tank in your attic pouring down through your ceilings.