radiator not heating up? Try replacing TRV head

explanation of how a thermostatic radiator valve (TRV) works , and how to replace the head on a Drayton RT212

[@AlexRocks24-7]

The body is trv4 🤓 I would have put atrv4 head on it 🤷

[@thornhillplumbing]

Same body as the rt212 , the east of the valves in the house are rt212 and the trv4 are more expensive 🤷