Green pipes?? Sticky residue?? WTF??

[Jennie]

Hi all, I did a LGSC today, on a 1-year-old Worcester combi.
Pics attached of the flow and return pipes to the boiler, coated with green powdery but dry residue. And also the pipe tray/cover, which had a sticky green residue. No other issues anywhere. But because it's just the central heating pipes affected, I'm a bit puzzled. Any ideas anyone?

 

[Burger]

Looks like flux or residue from a leaking condense.

 

[Jennie]

I thought flux too, but what's it doing around the compression nuts on the flow/return pipes.

 

[ShaunCorbs]

Micro weep on the connections

Someone didn’t pre wet the fibres

I believe leak sealer is green

 

[Burger]

I thought flux too, but what's it doing around the compression nuts on the flow/return pipes.

Could be as Shaun says, but I’ve known people to apply flux with their fingers and then it gets everywhere, a long shot but could happen.

 

[Brambles]

I would go with both Shaun and CBW - it is not verdigris ( copper reacting with Oxygen and moisture ) / that won’t form or adhere to brass fittings

 

[Jennie]

Thanks everyone. Your advice is so useful.

 

[Scott_D]

Really common on WB I find

 

[Jennie]

Really common on WB I find

Any reason why? (Other than flux or leak sealer)? I've not seen it before.

 

[Aire]

Micro weep on the connections

Someone didn’t pre wet the fibres

I believe leak sealer is green

Your supposed to pre wet fibre washers?

 

[ShaunCorbs]

Your supposed to pre wet fibre washers?

Helps them seal better by expanding them

 

[Ben-gee]

But don’t do it too far in advance or they turn to mush and fall apart.
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Some seem to have a coating on and take ages to seal up , others double in size from moisture in your fingers - don’t pre wet the latter.

 

[Stigster]

I've seen leak detector spray leave a green sticky weirdness on pipework before after it was prayed on and then just left. Could that be the cause here?