Identify the fault before choosing a valve
A leak at a pipe connection, a valve that will not turn and a room that overheats are different symptoms. A thermostatic head may be replaceable on its own, but only when it fits the existing valve body. Send close-up photos of both ends of the radiator.
TRVs and room controls work together
A thermostatic radiator valve adjusts flow at a radiator; it does not replace every function of the central heating controls. The position of the room thermostat and the wider system arrangement need to be considered when deciding where valves should be fitted.
Understand installation and finishing
Changing a valve body may require draining part of the heating system, refilling and checking for leaks. Pipe sizes, valve orientation and old fittings affect the work. Agree whether the visit includes system checks, balancing or any further fault investigation.

