Fitting a Thermostatic Radiator Valve

Project Essentials.
Adjustable spanner.
Wire wool.
Thermostatic radiator valves.
New connector if required.
PTFE tape.


There are still many central heating systems that are controlled by a single thermostat. This is usually fitted in somewhere like the hallway. Unfortunately, this arrangement doesn’t take into account local variations in temperature, and some rooms may become too hot or cold which can mean that you have to keep adjusting the manual radiator valves. The answer is to fit thermostatic valves, which open and close automatically in response to room temperature. In many cases, a thermostatic valve will be a straight replacement for an existing manual valve. South Bank Plumbers can fit thermostatic valves throughout a system.


1). Firstly drain the heating system. Disconnect the valve from the radiator by unscrewing its cap-nut, but before releasing it completely, slacken the nut holding the valve to the pipe. Then unscrew both nuts fully and lift the valve together with its cap-nut and olive from the end of the pipe.

2). Clean the end of the pipe with wire wool and slip the cap-nut and olive of the new valve onto it. Hold the valve in place and screw the cap-nut onto the valve, making sure the olive is seated properly. Do not tighten the cap-nut fully at this stage. A South Bank Plumber is trained on radiator valves.

3). Fit the radiator with a new connector if necessary, wrap a few turns of PTFE tape around its threads, align the valve and start turning the cap-nut onto it. Then tighten both cap-nuts fully. Refill the system checking for leaks and finally set the thermostat valve in accordance with the manufacturer’s instructions.


NOTE: PTFE tape is used by plumbers to ensure a watertight joint on threaded fittings. Usually it is wrapped around 5 times clockwise before the fitting is screwed together.