small central heating tank overflow pipe constantly dripping

[chimo]

Hi all, hope someone can help me with this ongoing problem. The central heating overflow pipe drips constantly even with central heating off and water cold with no immersion on. Its an oil fired 30 year old system which also has a back boiler. I have emptied small tank to well below overflow level and checked that overflow valve was opening/closing properily and it seems to be working fine. The j shped pipe over the small tank is bone dry. The only thing that i hav'nt checked was to drian the small tank completely to see if the water is entering the bottom of the small tank the pipe feeds to the central heating system. How can the small tank be filling with water with no heating/pump running. Anybody any ideas?

many thanks

 

[Grumpy old Plum]

Hi
sorry t here you are having problems is the cold water storage tank water level higher than the small header tank if so I believe you may have a hole or perforation in the indirect part of your hot water storage cylinder best to get a qualified plumber in

 

[stevetheplumber]

ballvalve

 

[Ermintrude]

Or leak in coil.

 

[chimo]

Thanks for all your replys. With heating/pump off and water cold I drained the small central heating tank today and the pipe going into the bottom of the small tank is dribbling water into small tank. Ballcock working fine. Is the coil leaking water into cenral heating system?

many thanks

 

[Ermintrude]

Sounds like it.