Installing a thermostatic valve


Job description: Gain comfort by replacing your ordinary radiator valve with a thermostatic valve. Cut your energy bills by 10% by installing thermostatic valves which will help you regulate the temperature of each room. TRVs should be set at a level that gives you the room temperature you want.

Skill level: 1 – Beginner

Materials required:

  • Adjustable wrench
  • Screwdriver
  • Small recipient
  • PTFE tape
Step by step guide to installing a thermostatic valve:

1. The radiator must be bled and the heating circuit drained before replacing the valve. You need to make sure that the new valve is the correct type and size, and that it will fit without having to make any modifications to the pipe work.

2. Take the old valve out. Use a bleeding key to undo the valve at the top of the old radiator, then use a radiator spanner to undo the joints.

3. Remove the original mounting by removing the central screw of the valve head. Put some sheets around the floor in case of spillage.

4. Place a plastic container under the joint to collect any remaining water.

5. Use an adjustable wrench to hold the body of the old valve and loosen the nuts that hold the valve onto the copper pipe and to the adaptor that's fitted into the radiator. Unscrew the adaptor from the radiator.

6. Fit the new adaptor, cap nut and olive (the metal sealing ring on the pipe.) onto the radiator.

7. Clean the threads located internally using a clean cloth and then wrap some PTFE tape around the adaptor threads in a clockwise direction. Wrap the tape around at least 6-8 times.

8. Screw on the new adaptor and tighten.

9. Remove the old olive and cap nut from the copper pipe and replace with the new set.

10. Fit the thermostatic valve, then tighten the cap nut between the adaptor the valve, holding the body of the valve with one wrench. Finally tighten the cap nut between the pipe and new valve.

11. Refill the central heating system and check for leaks. Set your living room valve to fully open and your bedrooms to a lower setting.

If you have a spare bedroom, put the valve on the frost or minimum setting and keep the door closed so that the adjacent radiators don't try and compensate for the drop in air temperature.

You should not fit a radiator thermostat in the same room as the room thermostat that controls the overall boiler output.

Unless you are good at DIY, you might want to contact a local heating specialist.

The information provided in this guide is to be used strictly for guidance only. We recommend you always read the manufacturer's instructions.