Leak between top up cistern and main tank

There is a tiny leak at the join between the top up cistern and the main tank. So slow that the water evaporates - puddle about the size of a 50p piece. Can this be repaired without replacing the whole tank?

You mean at the pipe joint? Or is the tank itself leaking?

The joints can be re-made but the tank will need replacing if it has a perforation. Sealing with silicone on the inside often works but can't really be regarded as a permanent fix.

Cheers, Mike

I have exactly the same problem. But I'm often away, and turn the system off then. So the weep then creates quite a big puddle, as there's no heat from the system to evaporate the leaked water. It looks like the weep is where the weld is between the header tank and the main one, but I can't be absolutely sure, as the water has created scale and rust all over the place, including where the pipe goes in. When you say a silicone seal can be used, Mike, I assume you are suggesting this be applied to the exterior? Mine is about 10 years old, so I'm not thrilled that I might need a whole new one. How much, very roughly, is it to replace the whole thing?

Hopefully, Mike the Boilerman will respond to my query as I notice that paulgodier's similar message of 04 May 2009 has not been answered.
In my situation, the weeping joint is on top of the lower tank and has become encrusted with limescale.
Additionally, the flat top-surface of the lower tank has become rusty and in places some of that corrosion has become flakey.
Although hot water is still being produced seemingly ok, do either of these conditions indicate serious hidden problems ?
Can the joint just be remade ?
Will the corroded top surface need any special treatment ?
Or, will the whole thing have to be replaced ?

Is the leak visible? I.e on a pipe joint. If so then it can be repaired, if the leak is below the casing then you wont be able to be repair it.

As for the rust, it depends how bad it is, you can either sand back to metal and repaint it, or remove the the header tank and fit a small ply board then refit the header tank.

I hope this helps

Gary
MK Group

Just try what Gary said, or call us on 0800 046 1241 and we can explain it to you.