Radiator Valve?

[Jo]

Hi

I hope someone can help me. We have a radiator which is leaking from where the pipe joins the valve (the bit with a white knob). The leak appears to be coming from underneath the nut.
This radiator has a drain off bit (on the valve where the leak is) and we had someone do a powerflush/clean thing a while ago. Afterwards I noticed there would occasionally be a little green puddle on the floor (tiled). However, it has now developed into a proper leak.
We haven't tried anything yet as I am unsure if it's been undertightened and therefore easily rectified (?) or overtightened and split.
It's quite an old system and I thought maybe we could just turn that one off but I can't move either of the white knobs.
Is it possible to put some sort of sealant around the pipe or do we need to get someone in and have the valve replaced.
Huge apologies for not knowing any technical terms. Please reply in laymans terms!
Many thanks

 

[Paul Barker]

You are unlikely to do any damage if you try tightening the nut. Get a feel if it seems relatively easy continue until it is hard for you. If you use an adjustable spanner it will slip off the nut when you have it about right.