Yellow residue on copper pipe joint

[Newby2]

hi
As shown in the photo, there is some yellow powdery residue around the valve of one of the central heating copper pipes in the airing cupboard. It has been there for many years and so far there is no leak (it’s dry). Could someone tell me what it is and do I need to do anything about it?

Many thanks.

 

[undertrained]

Hello Newby2,

Looks like atmospheric corrosion to me, don’t really need to do anything, but if you wanted to you could get it replaced, as it may sieze up the gate valve.

 

[Jackrae]

Dried corrosion inhibitor from an old weepage that has sealed itself. Let sleeping dogs lie.

 

[Madrab]

If it's all dry and the valve works then just clean the scale off and don't worry about it.