Lockshield replacement advice

[elmocambo]

I'm redecorating the front room and have found one of the radiator trv leaking when adjusted, so I have decided to replace the trvs on all three radiators given there age, should I replace the lock shields also?

 

[ShaunCorbs]

Your draining down so yes 15mm or 10mm ?

 

[elmocambo]

15mm x 21mm
Screwfix has flomaster but I'm not sure if this is a reliable valve, it's difficult to source other makes locally

 

[ShaunCorbs]

Yep there the ones I use downstairs I fit the drain off type

 

[elmocambo]

Yep there the ones I use downstairs I fit the drain off type

Thanks
I have an external ground standing oil fired boiler, maybe I don't need a drain off at the radiator

 

[elmocambo]

This may sound like a daft question, but how do you remove the control knob to convert it into a lock shield?
I'm not sure if it is a one piece molding, or is that a cap or a flash line? there is no way to prise it of

 

[elmocambo]

Ah I have found out they are push fit