How do I change my radiator valve?

[Swoph]

Hello! I have just bought a new radiator valve to replace my old one which is broken. (The TRV pin is stuck and I can move it both up and down with pliers but it does not spring back by itself even after lubing). I have actually bought a lockshied - I'm sure thats what it's called.

The actual changing of the valve is pretty basic I'm sure, just a case of unscrewing and screwing back on....however - I need to know about draining the radiators etc.

Do I have to drain them ALL!? And if so how do I do this? Is there one radiator that will have a draining tap and its just a case of opening this tap and draining it until nothing else comes out and then I can get to work replacing? Also...after the deed is done, do I then just refill them by turning the tap by my boiler until the boiler pressure shows normal?

Sorry for being such a damn novice! Thank youuuu

Extra note: In case it make a difference, I have a gas combi boiler.

 

[clf-gas]

Drain the heating system from lowest point, may or may not have a drain valve.
Change old for new and put inhibitor in rad.

read in here for refilling and bleeding air from heating

//www.diynot.com/forums/viewtopic.php?t=37170

 

[Deleted 98600]

plug the cold feed and vent from the central heating tank in the loft, to create a vacum, this will eliminate the need for a drain down and then putting inhibitor in the system

 

[nitro23456]

plug the cold feed and vent from the central heating tank in the loft, to create a vacum, this will eliminate the need for a drain down and then putting inhibitor in the system

he has a combi

 

[clf-gas]

plug the cold feed and vent from the central heating tank in the loft, to create a vacum, this will eliminate the need for a drain down and then putting inhibitor in the system

Read it again

 

[Deleted 98600]

didnt read that haha