Novice question - how do i tighten this fitting?

[Pablo]

After the recent cold spell I had a link in an out house. The fitting is still leaking (see attached). I'm not familiar with the connection type. I've tightened the top nut but it is still leaking, apparently from the black and white assembly part. Do I need a new connection or am I supposed to tighten the black and white assembly some how? Any advice gratefully received.
Cheers.
Paul.

 

[ShaunCorbs]

If it's been damaged by the frost best replace the fitting

 

[Pablo]

Thanks for the prompt reply. Is there a name for this type of fitting?

 

[ShaunCorbs]

yea its an imperial to copper adaptor

something like this will do the job

Philmac PP Joiner UTC x POL

or time to call a pro in

 

[sammathias]

looks like 3/8th to 15mm. I imagine in the frost the 3/8th pipe has pulled out of the fitting. turn water off, undo white nut, push black pipe all way in and tighten white back up. see if that sorts it.