Losing water in the Central Heating Tank in Loft.

[kev999]

Hi,
I have noticed by chance that water has been going down in the C/Heating tank in the Loft. I shut off the water going to it to replace a radiator, did the work, filled the tank again, bleed the rads but never started the heating back up. Went back to the tank because I had shut of supply to it and have noticed that the level had gone down a bit and the ballcock let in about another bucket of water before stoping (it's a 25 gallon tank). That's over about 4 days.
I have no leaks visable anywhere, the thing that worries me is I have a stupid old house and at some time the floor has been screeded over with the pipes on the ground floor buried below.
Could they be leaking below the concrete screed? it is 8mm microbore.
Is there another reason why I lost the water?
Should I just start the heating back up and keep an eye on it?
I'm I in trouble?

 

[gas4you]

If you have thoroughly checked all the rads, rad valves and other visible joints etc, then unfotunately it is pointing to a leaking pipe in the screed, or at least somewhere you cannot see the leak.

Have you checked around the F & E tank to see if it is leaking its self? Any damp patchs on the ceiling etc?

 

[kev999]

There is no leak by the tank or anything visable.
Is there any thing I can use to seal the leak without digging the floor up?

 

[seco services]

you can get leal sealers.

http://www.fernox.com/?cccpage=leak_sealer_ls_i&sub=4

i always prefer to do the job properly

 

[gas4you]

You could try Fernox or Sentinel leak sealer, but these never seem to work for very long, or if it is more than a pin hole leak, in my experience.