Help - Overflow from cold water Storage tank in the loft dripping

wiseguy80

Hi,
We have a conventional boiler system with a cold water tank in the loft. There is a hot water tank a bit below it and a boiler in the kitchen. The overflow from the cold water tank is piped all the way out of the build.

Noticed that there is a continuous drip of water from that overflow pipe. It stops momentarily when the water is used (when I flush for instance) but then come up again. I had a look and the ballcock seems fine. there is no drip from it and it stops when it's level.

Any suggestion please? It's an old style old brass ballcock. Should I replace it? If yes, is it a diy not or should I get a plumber?

Thank you for your help

Le_Kirk

You are lucky it is only dripping, as that is a warning and will give you time to cure the problem, which is a washer on the valve at the business end of the ballcock. To change the washer you will need to find your stopcock for the incoming mains, normally in the kitchen under a worktop in a cupboard - mind your head! You will also need a new washer. Size will obviously depend on type/size of ballcock. Best to buy an assorted pack of washers if you want to do it yourself. You could call a plumber but make sure to tell them it is a non-emergency situation. You could try bending the ballcock arm down a bit and that will shut off the water a bit sooner and give you more time before the water reaches the overflow pipe. It will not be a permanent fix.

wiseguy80

Thanks Le_kirk.
I will see if I can bend it a bit to fix it for the time being. Any ideas on how much should a replacing a ballcock take?

maninthestreet

wiseguy80 wrote: »

Thanks Le_kirk.
I will see if I can bend it a bit to fix it for the time being. Any ideas on how much should a replacing a ballcock take?

All three ballcocks in my house started to fail within a few weeks of each other. The cost of replacing two of them (they broke when the plumber tried to take them apart), and replacing the washer in the other one was about £80.

chrisw

If you do it yourself, around 50p for a new washer or you can go the whole hog and replace the ball valve or float valve assembly for around £4 from Screwfix/Toolstation.

I replaced mine as the valve broke - it wasn't particularly difficult.

Annie1960

I got mine done on Friday. It cost £90, £70 labour (which is expensive down here) and £20 parts.

I probably could have phoned around and got it done cheaper, but I know from experience the cheapest plumber call-out in this area is £60, so I could have saved £10 but spent a lot of time on getting someone else, who may not have turned up.

wiseguy80

thank you all

wiseguy80

So, I had a plumber fit in new ballcock. He charged me £60 + VAT. However, still have the water dripping out. He suggest, it might be the coil in my hot water cylinder. Seems expensive to me. Does anyone know how much I am looking at in case it is that problem? Thanks.

Le_Kirk

Hmmm, if it is the coil, that could mean replacing the whole cylinder! Mystified as to why plumber thinks it is affecting the overflow. If the overflow pipe is connected to the cold water tank, the only way water can go down the overflow pipe is if the water level rises above the bottom of the overflow pipe. This can be checked visually. If the ballcock stops the flow of water into the tank and the water level keeps on rising, something else is adding water to the tank. What other pipes feed into your cold tank? I suppose it's feasible that a split coil could be feeding water from the central heating system (boiler) into the tank and back up the pipe between cold tank and hot water cylinder. If this is the case, you would be using water (from the header tank) or pressure from the boiler depending upon the type of system.

JP08

Your plumber could be right. Next door neighbour had a similar problem. The heat exchanger coil in the hot water tank had a small hole. So the water from the heating side of the system, being at a slightly higher pressure than the water side due to the header tank for the heating being higher than the cold water tank, was entering the hot water tank, and hence gradually back filling up the cold water tank in the loft.

Solution in that case is almost certainly a new hot water tank.