Changing a radiator valve is a common home maintenance task that can fix leaks, improve heating efficiency, or upgrade to a thermostatic radiator valve (TRV) for better temperature control. Whether replacing a faulty valve or upgrading to a modern one, this guide provides a step-by-step approach to safely and effectively changing a radiator valve.
1. Tools and Materials You Will Need
Before starting, gather the following:
- New radiator valve (manual or thermostatic)
- Adjustable spanner
- Pipe wrench
- PTFE tape (plumber’s tape)
- Bucket or bowl (to catch water)
- Towels or rags (to mop up spills)
- Radiator bleed key
- Plumber’s jointing compound (optional for extra sealing)
2. Turn Off the Heating and Isolate the Radiator
Step 1: Switch Off the Central Heating
Turn off the heating system and allow the radiators to cool completely to avoid burns and pressure build-up.
Step 2: Shut Off the Boiler (if applicable)
If your system is a combi boiler, turn off the water supply to prevent additional pressure.
Step 3: Close Both Radiator Valves
Locate the valves at each end of the radiator:
- Lockshield valve – Controls water flow balance. Use an adjustable spanner to turn it clockwise until fully closed.
- Manual or thermostatic valve – Turn to the lowest setting or off position.
3. Drain the Radiator
Step 4: Release the Water from the Radiator
- Place a bucket or bowl under the radiator valve to catch water.
- Use an adjustable spanner to loosen the compression nuts on the valve.
- Open the radiator bleed valve (top of the radiator) using a bleed key to let air in and allow water to drain fully.
4. Remove the Old Valve
Step 5: Unscrew and Remove the Valve
- Once drained, completely undo the compression nuts on the radiator and pipework using a spanner and wrench.
- Carefully pull the old valve away.
Step 6: Clean the Pipe Fittings
- Wipe off any old PTFE tape or jointing compound from the valve connection and pipe threads.
- Ensure the area is dry and free of debris.
5. Install the New Radiator Valve
Step 7: Apply PTFE Tape for a Secure Seal
Wrap PTFE tape (6-8 turns) around the radiator tail thread to ensure a watertight seal.
Step 8: Attach the New Valve
- Connect the new valve to the radiator inlet and pipework.
- Hand-tighten first, then use a spanner and wrench to secure the compression nuts.
Step 9: Reopen the Lockshield Valve
- Turn the lockshield valve back to its original position (usually half to one full turn).
- If installing a thermostatic radiator valve (TRV), set it to the correct setting.
6. Refill and Check for Leaks
Step 10: Refill the Radiator
- Close the bleed valve and slowly reopen the thermostatic or manual valve to allow water to flow back into the radiator.
- Check for leaks around the new valve connections.
Step 11: Bleed the Radiator
- Use a bleed key to release trapped air from the radiator.
- Keep a towel handy to catch any escaping water.
Step 12: Turn the Heating System Back On
- Once refilled and bled, turn the heating system back on and monitor the radiator for even heating and any leaks.
7. Final Checks and Adjustments
- Ensure there are no leaks around the new valve.
- If the heating system has lost pressure, top up the boiler pressure (for combi boilers).
- Adjust the lockshield valve if necessary for system balance.
- If upgrading to a thermostatic radiator valve (TRV), test different temperature settings.
Conclusion
Replacing a radiator valve is a straightforward DIY task that can improve heating efficiency and prevent leaks. By following this step-by-step guide, you can safely replace your radiator valve and restore proper heating function.
If you need professional assistance or advice on heating system improvements, consider consulting a heating specialist or plumber to ensure the best results.
