Knowing how to turn a radiator off is a quick and easy job that can save you money and energy by preventing the heating of unused rooms. You might also need to turn a radiator off to perform essential maintenance, isolate it for balancing, or address a leak. This guide provides step-by-step instructions for operating both the Thermostatic Radiator Valve and the Lockshield Valve.
How to Turn a Radiator Off?
Knowing how to turn a radiator off can save energy and help with maintenance, balancing, or leak control. Follow these simple steps to turn off or fully isolate your radiator.
What are the Two Radiator Valves
Every radiator has two main valves that control water flow.
Flow Valve – Supply Pipe
This may be a numbered TRV or manual valve where hot water enters.
Lockshield Valve – Return Pipe
Usually hidden beneath a plastic cap, this valve controls the water leaving the radiator and is used for balancing.
Method 1: Turning Off a Radiator with a Thermostatic Valve
Most modern radiators are fitted with TRVs for room-by-room heating control.
Step 1: Turn the Thermostatic Radiator Valve Down to Zero
Locate the numbered valve (0–5) and turn it clockwise to 0 or *.
If unnumbered, turn it fully clockwise until it stops.
Step 2: Turn the Lockshield Valve Off – If Isolation Is Needed
Remove the plastic cap from the opposite side.
Use a spanner or pliers to turn the spindle clockwise until fully closed.
Method 2: Turning Off a Radiator with a Manual Valve
If your radiator has a manual valve instead of a TRV:
Closing the Manual Valve
Twist it clockwise until it stops to shut off water flow.
For Full Isolation
Follow the lockshield valve steps outlined in Method 1.
Turning Off a Heated Towel Radiator
Towel rails use the same valve setup as standard radiators.
Turn the TRV or manual valve clockwise to shut it off completely.
Special Situations
Turning Off a Radiator When the Thermostat Is Broken
If heat continues despite turning the TRV off, the internal pin may be stuck.
- Remove the lockshield cap
- Turn the spindle clockwise to isolate
- Note the number of turns for later re-balancing
- Replace the faulty valve
Turning Off a Radiator When It Leaks
If the radiator is leaking:
Valve Leak
Turning the valve clockwise may temporarily stop the leak. Replace the valve as soon as possible.
Corrosion Leak
If water is coming through a hole in the radiator body:
- Closing the valve stops hot water entering
- But internal water will continue leaking until drained
- Contact a Gas Safe Registered engineer
Is It Ok to Turn Off Individual Radiators?
Yes, it is safe and energy-efficient to turn off radiators in unused rooms.
Efficiency Tips
- Turning radiators off reduces unnecessary heating
- Always keep doors closed in unheated rooms to prevent cold air drifting out
Frequently Asked Questions
What is the purpose of radiator valves?
Radiator valves control hot water flow into the radiator. The flow valve manages heat output; the lockshield valve balances system flow.
What do the valves do on a radiator?
They regulate or stop the hot water entering the radiator, enabling full control over temperature or isolation.
Can a broken thermostat be fixed easily?
Replacing the TRV head may solve the issue, but if the metal pin is stuck or leaking, the entire valve must be replaced.
Conclusion
Turning a radiator off is simple—close the TRV or manual valve by turning it clockwise. For repairs or leaks, fully isolate the radiator by also closing the lockshield valve. Turning off radiators in unused rooms is safe and energy-efficient as long as doors are kept closed. Understanding both valves gives you full control over heating zones, helping you save energy and money.
