Radiator leak stopped on its own. How?

[veedee]

Removed towel rad to decorate.

After refitting the rad, there was a weeping, persistent /leak at the valve.

However, after bleeding the rads and running the central heating for about 20 mins, the leak stopped on its own.

This. Isn't the first time that this has happened to me.

Can someone whether it is common for a plumbing leak to seal itself? Is there a scientific explanation for this phenomenon?

 

[DetlefSchmitz]

As I understand it, water leaks out and starts to evaporate, leaving behind a deposit of, e.g., calcium carbonate and doubtless loads of other things. These stay behind and tend to fill the gap where the water leaks from.

 

[MickyP10]

It'll probably leak again when cold.

 

[Jurassicspark]

If it's a very small leak, I guess its possible that rust and scale could be drawn to the leak and eventually plug it.

 

[veedee]

It'll probably leak again when cold.

You mean when the pipe is cold again after the central heating is off?

If it's a very small leak, I guess its possible that rust and scale could be drawn to the leak and eventually plug it.

That seems like the most logical explanation. But this always occurs within 30 mins. Can old and new rust/scale form in that quickly?

Have any other plumbers experienced this?

 

[MickyP10]

Yes. Leave heating off for a couple of days. Is the leak back?

 

[veedee]

Yes. Leave heating off for a couple of days. Is the leak back?

No. The area is bone dry

This is fascinating to me. Experienced plumbers must have noticed this occurrence in their daily work.

In my limited plumbing work, this has occurred at least 3x. Each time, a weeping leak at the rad valve just magically seals itself.

This also took place when we installed a magnetic filter to the boiler. Weeping, persistent leak just sealed itself within 30 mins.

 

[martygturner]

That's why god invented jointing compound and ptfe tape.