Re positioning 15mm solderd joint

[madmart]

I need to swing out a 90 15mm copper fitting to fit a new radiator valve (marked 1 in photo).

Can I apply heat to the 90 degree joint to loosen the solder and pull the 15mm pipe
to the correct position so the valve fits the rad?

 

[Riley]

You can certainly sweat the joint apart yes

 

[Gray0689]

But you will have to drain down first

 

[drip-dry]

You will find for best results,clean around joint with wire wool,add flux and then heat and move,then add a little more solder to outer fitting

 

[Best]

I would recommend you drain the system to below that level and then sweat it off carefully without disturbing the tee below it with too much heat.
Then clean the copper pipe end with emery cloth & steel wool or similar (often find fittings not soldered fully & pipe has dirty patches) & use a brand new fitting.