Take no notice; no expert myself, but copper DOES turn green when it's oxidising (ie - erroding) and unless I'm mistaken it looks like you have some green spots on your pipe.
Suggest you clean off oxidising areas with wire wool and if they reappear call out a central heating engineer as there may be a lack of inhibitor in your system.
Inhibitor helps reduce the unavidable corrosive decay of copper in contact with water, oxygen (as an element of water) and external corrosive catalysts such as excess flux - a paste used in copper soldering which should ideally be flushed out of a system by the installer before commissioning, but rarely is due to price, time and general lack of attention to detail.
Its probably nothing but clean it, check it and if it keeps turning green
(oxidising) act on it.
Suggest you clean off oxidising areas with wire wool and if they reappear call out a central heating engineer as there may be a lack of inhibitor in your system.
Inhibitor helps reduce the unavidable corrosive decay of copper in contact with water, oxygen (as an element of water) and external corrosive catalysts such as excess flux - a paste used in copper soldering which should ideally be flushed out of a system by the installer before commissioning, but rarely is due to price, time and general lack of attention to detail.
Its probably nothing but clean it, check it and if it keeps turning green
(oxidising) act on it.
