Radiator has started making a pinging noise

[thesmoothound]

Hi,

My double convector radiator has started to make a loud ping about 10 mins after the heating has gone off. It has been installed fro about 3 years and never been a problem. It is just one loud ping and not a constant. It sounds like the metal pinging but everything seems secure.

Any suggestions?

Thanks

 

[easyflow]

TRV fitted ?, expansion and contraction, buffers not in brackets ? ghost ?

 

[picasso]

Its trying to locate a submarine in your header tank.