Drip, drip, drip.

[terryplumb]

What he said ^^^

 

[bolo 2]

Wrap a piece of tissue paper around the compression nut ,not as low as the soldered elbow. If the compression joint is leaking it will get wet.

It would appear that the tissue has already taken on a pale green tinge. Can't say that the tissue feels damp but will leave it until tomorrow then check furt.

 

[Madrab]

Can anyone tell me where the green colour in the drip comes from?

Invariably it's because someone didn't clean off the flux properly when they soldered the joint. Flux is acidic and it corrodes the joint creating that patina. It's like when copper roofs go green because the rain in cities is typically slightly acidic.

Looking at it, it doesn't look like the green's coming from the nut area, rather lower down near the soldered joint?

 

[bolo 2]

Invariably it's because someone didn't clean off the flux properly when they soldered the joint.

The valve was fitted almost 2 years ago. Would it take that time for the result of not cleaning off the flux properly to show?

Flux is acidic and it corrodes the joint creating that patina. It's like when copper roofs go green because the rain in cities is typically slightly acidic.

A good description follwed by an even better analogy.

Looking at it, it doesn't look like the green's coming from the nut area, rather lower down near the soldered joint?

Having just had another close look, I've got to agree with you. The reason for that is I can see that the green is coming from both ends of the joint with a clear break in the middle. However the drip has stopped but I can't think why. If the water was coming from the soldered joint is there anything I can do to stop it should it start again?

 

[Madrab]

If the water was coming from the soldered joint is there anything I can do to stop it should it start again?

replaceing/re-soldering the joint is the only way to repair a soldered elbow I'm afraid.

 

[bolo 2]

replaceing/re-soldering the joint is the only way to repair a soldered elbow I'm afraid.

No drips yesterday, none today and tissue dry. Can I leave this until boiler service at end of March next year? And clutching at straws, given that there has been very, very few drips, is there any chance that this could be condensation?

 

[Madrab]

Wouldn't think it's condensation, not on a central heating pipe especially if it's heated. That would usually happen on a cold water pipe in a moist room.

It may keep until March as it's now dried up but can never be sure with these things. Just try not to knock it or unsettle it and keep a close eye on it.

 

[bolo 2]

shut the valve off and take the nut off and wrap the reducer in a couple of turns of gas PTFE tape and nip it back up

Early this morning the tissue and the red platic lid I sat below to catch any drips, were both dry. Back again an hour later and immediately spotted that there was a new drip and that the tissue was wet. That being the case, I am guessing that the leak does come from the nut and if it gets too bad I will have a look at your suggestion and perhaps have a go.