Ballcock trouble

liames

Fitted a new ballcock and arm in the small central heating expansion tank in loft as the overflow was dripping. This has not solved the problem and the dripping is constant when central heating is on. Any ideas telephoned three plumbers but they all said it was an easy job to do youself.By the way it is a Worcester 24cdi combi boiler.

teddyco

When you say "overflow dripping" do you mean that the level in your heating expansion tank is too high and hence continues to drain out? If this is the case, you need to adjust the ballcock so that it shuts off the inflow before it reaches the overflow. There should be an adjusting screw on it.

chrisw

Did you change the washer/diaphragm when you changed the ballcock? It's usually located in a brass cylinder inside the valve and slides to press against the inlet nozzle as the ballcock rises. The surface on the rubber disc had perished on mine, so water could still drip past even when it was pressed hard against the nozzle.

weekendwarrior

Are you sure you have a combi?

Never heard of a combi having a "small central heating expansion tank in loft ", they are normally just plumbed into the rising main and have a seperate "sealed" circuit for the central heating.?

Ball valves often get worn internally and changing the ball float, arm and even the washer will often not remedy the situation. It is often much easier to replace the whole ball valve assembly, you can easily do it with the water isolated and two large adjustable spanners/ water pump pliers etc.

It is only about £2.00 for the whole ball valve assembly- http://www.screwfix.com/app/sfd/cat/pro.jsp?id=14542&ts=7288

There are a couple of different types, so make sure you get the correct one!

Good luck

liames

Other half useless at diy. Never mind changed ballcock, arm and part which included brass cylinder with rubber disc. It was all bought as one peice. The water level in tank looks okay. Where is the adjusting screw please?

liames

Thanks weekendwarrior. The screwfix picture of the whole ball valve assembly is exactly what I bought. Took the old one into Plumbers merchants and they assured me it was the right one that I needed. No other tanks in loft apart from this very small one.

Mikeyorks

No adjusting screw on these (only the plastic ones). You need to bend the brass arm downwards to adjust it. But don't do that if the water level with the ballcock valve shut - is below the overflow level.

Do however check the brass cap farest away on the whole assembly. The ballcock is usually delivered with that only finger tight - so it will leak and gradually overflow?

That apart - idealess!!

liames

Thank you everybody. Fingers crossed problem has now been solved