Ballcock trouble-what's the small tank for??

simonhgreen

Hi all

Noticed my overflow dripping this morning but had to get to work. Fortunately it hasn't got any worse.

I've been in the loft & there are two water tanks, one biggun & a little one next to it.

In the little one the ballcock is under the water and the level is enough to get it trickling through the overflow hole.

Am I right in thinking I need to replace the ballcock & arm and is it as easy as knocking the split-pin out at the valve and replacing the arm & ball with a new one?

How do I stop the water coming into the tank when I remove the old ballcock (it's not at the bottom of the tank, just under the water) and before the new one is attached?

I thought it was something to do with the hot water, so I turned a tap on to try and reduce the level in the tank but it was the big tank that started filling.

Can anyone tell me what the little tank is for?

Any advice much appreciated.

Rickycowslip

I'm not a plumber, but I too have a little tank and its the one that refreshes your heating system if for some reason you drain water from it (ie. the radiators) that's why it looks a bit dusty, cos its hardly ever used.

A quick fix that works for me is just to empty the little tamk until the level's below the inlet, then wiggle the lever until it stops water coming through

a&akay

It's your central heating expansion tank. When your CH heats up the water expands into this tank. It also feeds your CH system when you bleed off air in the rads for instance. It is unlikely to be the ball itself. You can unscrew this off the rod and shake it. No water - no leak in the ball. It is likely to be the washer which will be either damaged or compressed and allowing water to pass. Turn off water off at your house stopcock. Remove split pin with pliers, take cap off the end of the fitting. Take rod out of the piston. Slide piston out of the fitting. You will see a small rubber washer in the piston. Replace it and reverse the dismantling procedure.

Paul_the_Painter

All totally true a&akay, but another way to look at it is, that a new ball !!!! valve and ball is about £7.00 from B&Q or Wickes, so why not replace the whole thing and forget about it for the next ten years? If your up there doing the job, might as well just replace the whole thing. Not exactly money saving, but when you are looking at such a small cost why skimp, peace of mind is worth a bit too.

a&akay

If the owner has the necessary hardware to grip both the fitting on the inside of the tank and another to tighten the nut on the outside of the tank wall sufficiently, so placing the ballvalve fiitting in the correct orientation for the ball and arm to operate in the small tank without binding on its walls fair enough. If this is not done, tightening the outside tap coupling is likely to rotate the ballvalve. If he doesn't want the expense of buying this hardware, a pair of pliers and a washer will do the trick.