What is making this noise in our radiator?

[Caz6]

Can anyone tell me what is making the noise in our radiator please?

It’s a large, downstairs radiator which has been bled. It’s been happening since we had a new boiler installed. It happens to a much lesser extent on a couple of other radiators. Immediately before this recording, the noise was insane for about 5 seconds. Like a firecracker going off.

 

[gas112]

possibly a blob of solder rattling about

 

[Caz6]

Ah good point, would that be a full draining to remove it?

 

[gas112]

Ah good point, would that be a full draining to remove it?

isolate just that rad take it outside and hose it through

 

[Caz6]

Ok thanks! Appreciate your advice