How do these elbows seal?

[terryturbojr]

I'm just coming to the end of a self build and went to turn the ufh on with the recent cold spell and there's a leak in the manifold where the elbow joins.

 

Does anyone know how these elbows seal?  I currently can't fully remove it to see (as wall behind blocks the turn) so wanted to confirm I need to take it off before I start cutting holes in the wall behind. 

 

Thanks

 

 

[dpmiller]

I *think* there's an O-ring in a recess behind the thin locknut IIRC. Try tightening the locknut a smidge...

[terryturbojr]

Cheers. I tightened that until it can't go any further and it still leaks so wondering if the o ring is missing. Will have to look at rates to take apart. 

 

Looking at it again after I posted I think I can use remove the whole pump assembly rather than having to cut a hole in the walk so the elbow can do a full turn.