Small hot water tank in loft dripping from overflow...

[The Dripping Tap]

Hi

The small water tank in the loft for the hot water is overflowing. I noticed a drip outside the house from this so replaced the ball valve, however a couple of days later i noticed the dripping had resumed and checked the tank to see the ball valve submerged....

I emptied out some water and put a cup in the tank under the pipe which also runs into the tank and put the hot water on for a short period and a little while later checked it to find some lukewarm water in the cup.

Any ideas on what the cause of this could be and how to fix the problem?

 

[halfway]

Have you added any rads or made any changed to the heating? May be as simple bending the ball valve arm a bit.

 

[The Dripping Tap]

Nope haven't made any changes at all, guess you mean to bend it downwards to lower the water level before the valve cuts off?

 

[halfway]

Yes. Just make sure that (after running a heating cycle) there is still water in that tank when system is cold.

 

[The Dripping Tap]

ok thanks will give that a go.

 

[halfway]

ok thanks will give that a go.

Also when the system is running hot, have a look at that tank to check if there is water coming out of the vent pipe. Shouldn't be.

 

[MANDATE]

Depends what is meant by ' replaced the ball valve' .
Some years ago I replaced the rubber valve disc only to find the leak had not been fixed.
The disc which is moved by the floating ball is pushed against a plastic nozzle and l found this nozzle had a groove worn in it on the sealing face.

 

[stardanny]

Is there a large water tank? Is the small water tanks lower than large one?

Please note that small water tank is for heating system which also heat the hot water as well via the coil inside the hot water cylinder. Large water tank is for hot water and cold feed if fitted.

If it continues to dripping, try turn off the supply to small tank and recheck later to confirm it's not the ballvalve. One possible cause for dripping is a pinhole leak on coil inside cylinder.

Daniel.

 

[The Dripping Tap]

Didnt get a chance to get up to the loft last night and there was no sign of dripping this morning outside

However pretty sure the ball valve inlet is fine


I think the problem is water coming out of the copper pipe to the left of it which i've numbered 2 in this rather crude attempt at a picture this was where i previously placed the empty cup which contained water a short while later having run the heating and hot water:

 

[halfway]

You have a problem that it will take a plumber to fix. You will need to find the cause of the pumping over. Could be lucky and might be circulating pump set too high. It could be the wrong pump for the system head. But most likely (seeing as you haven't had any work done on the system) a plumbing problem. It will most likely have caused sludge in your system. Most likely symptom is some radiators with cold spot in bottom centre.
Fix problem. Power flush. Inhibitor. Other solution might be to seal the system. Discuss it with plumber.

btw I like your illustration, esp water.