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A few months ago the cold water tank in the loft started to constantly overflow. We have not had time to look into this but presumably the valve or ball-cock needs adjusting or replacing?

When we went away for a few days we closed off the supply to the tank from the mains to stop it overflowing. When we came back my husband forgot to turn it on again and therefore ended up draining the tank to empty.

He then re-filled it and again it went back to constantly overflowing but now we only have a trickle of water to the upstairs cold water taps.

His theory is that there is sediment in the bottom of the tank which has now, because it was drained to the bottom, worked its way into the pipes and is blocking them, although there is no sign of muck coming through the taps.

[b]Is this right? If so, how do we clear it?
If not right, what else could be wrong?[/b]

Any thoughts and suggestions would be very welcome!

It mite be that your upstairs taps are tank fed,the problem sounds as tho yourve got an air lock caused when you drained down the tank.try running a hose from mains cold water to your basin taps to force the air out.Make sure some one keeps an eye on the tank so it dosent overflow.

Thanks for your suggestion. This could be the problem. However, I'm not sure we can force water from the mains cold tap into the upstairs taps because they are both mixer taps, ie both the sink and bath tap is one large tap which mixes the hot and cold sources. So, our hose may not fit onto these taps but also we would be forcing cold mains water into the hot water system as well as into the pipes leading to the cold water tank. What do you think?

in that case,you would better calling a plumber in to see if he can rectify the fault,he mite be able to pull the water thru from the cold feed tank without a deal of trouble.good luck

Fiona
b4 you fill the tank fit a new float valve to the tank to stop it overflowing then if you have an outside mtap then you could fill it from that using the hose fitting,if the hose wont fi over the tap outlets,let me know how you get on and if ou have any more probs let me know if you live near Penzance and i'll come and have a look, only kidding.

Cheers
Mark

hi i agree with mutley the chances are its air as the outlet pipe from the tank is normally a few inches up from the bottom of the tank
try blocking the outlet of the tap open the cold side and then the hot side you may get the hot to push out the air lock for you
bob

Yup, its an air-lock.

As for the over-flowing, the easiest (and cheapest - only a few pence) fix is to replace the washer. There is (usually) no need to replace the whole ball-cock assembly.

To do this:-

1) Turn off the water supply.
2) Remove the ball-cock (by removing the split-pin).
3) Unscrew the round retaining end (using mole grips).
4) Slide out the piston (using a nail or small screw driver).
5) (using 2 pairs of pliers) unscrew the piston and replace the washer.
6) Re-fit everything.
7) Turn on water supply.

This will take you 10/15 minutes :-)

MOT

pliers,mole grips, pistons.cheaper and more effective to replace whole unit

On one of the mixer taps, open the hot water tap - place your hand over the end of the tap and then open the cold water tap. You should be able to get the cold water to back fill the hot water pipes clearing the airlock.

Can be abit tricky and you may get wet, but it can be done.