How To Turn A Radiator Off DIY Step By Step Guide

James Elston
Written by James Elston
Updated on 23rd February 2024
Posted on 4th February 2024
How To Turn A Radiator Off DIY Step By Step Guide

How do I turn a radiator off? – Our simple guide to turning of a radiator

Radiators do a good job of keeping your home warm, and that’s great in the winter. However, it may be necessary to turn down or even turn off your radiator in July through August if you live in the UK because these are the hottest months.

There are several other reasons you might want to turn off your radiator, even if it is in the middle of winter.

Perhaps, you want to go on an extended holiday and don’t want to keep your radiator running to reduce energy consumption. Or some rooms in your home are currently unoccupied and do not need heating.

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Our Expert Gas Safe Engineer Says:

If you're thinking about turning off a radiator, it is relatively simple for someone with some DIY know-how. If you are unsure at all, you should always call in the professionals to prevent costly damage or repairs.

James Murfin

Gas Safe Registered Heating Engineer

If your doing this to keep energy bills down as you have an old boiler, get the latest new boiler costs here to see if you need a new boiler as it may be worth your while and save you from having to resort to fiddling with your central heating system day in and day out.

Whatever the reason, our guide will show you how to turn a radiator off. You’ll also learn how to turn down your radiator, even if it doesn’t have a thermostat valve.

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Turning Off a Radiator vs Isolating a Radiator

Typically, you want to turn off your radiator to stop heating a room. This usually means turning off a radiator valve but not completely shutting the flow of hot water.

The right time to completely shut off the flow of water is when you are trying to isolate a radiator. This could be because you are fixing a pipe that’s leaking or in the radiator, removing the radiator for decorating or replacing an old radiator.

If you shut off water flow entirely when you meant to turn off your radiator valve, it can cause the water in the radiator and pipes to freeze and expand. This may crack or rupture the pipes and metals, leading to expensive repairs.

Isolating a radiator is often a more complex process than turning down or turning off your radiator. However, anyone can isolate their radiator if they are careful enough to follow all the procedures. We’ll briefly discuss the steps in this guide, but for now, let’s focus on how to turn a radiator off or turn it down.

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Understanding Radiator Valves

man adjusting radiator valves

A modern radiator does not have too many moving parts, yet each is essential to the smooth running of the heating appliance.

Usually, the only parts you can adjust on a radiator are the valves. Since turning off a radiator usually means turning off the valves, let’s quickly see what the different radiator valves are and what they do.

There are a handful of radiator types, but you can categorise all of them into three main types, namely, thermostatic radiator valve (TRV), manual valve, and lockshield valve. Each of these works in a similar fashion as taps, allowing you to control the heat level from the radiator.

Thermostatic Radiator Valve (TRV)

A thermostatic radiator valve is fitted with a built-in temperature sensor that automatically maintains your preferred temperature setting by adjusting the heat output from the radiator.

The TRV provides zoned heating from a central heating system, and you can turn the valve handle to set the temperature you want. In addition to being simple to use, TRV is environmentally friendly. The valve usually has a numbered dial and can be straight or angled.

The Manual Valve

The manual valve controls the flow of water into the radiator. It allows for a constant heat level, meaning you must physically turn the valve to adjust the heat output. The manual valve can be fitted straight or at an angle, depending on the radiator and how best the valve must connect to it.

The Lockshield Valve

The lockshield valve regulates how much heat the radiator gives off, balancing the system. It is opposite the manual or thermostatic valve. Whatever you do, avoid adjusting the lockshield valve when turning off or turning down your radiator. Only use the lockshield valve when you want to isolate a radiator.

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Identifying Radiator Valves

Figuring out which valve on your radiator is the lockshield, thermostat, or manual valve is important to prevent confusion.

The thermostatic and manual valves usually have an easy turning mechanism. This feature is typically a numbered dial on the thermostatic valve.

The lockshield valve doesn’t have an easy turning mechanism, and as with the manual valve, there is no numbered dial. Instead, the lockshield valve has a plastic cover or cap that protects it. The cap is the actual “lockshield,” designed to prevent owners from accidentally changing the settings.

Another visual difference is that the thermostatic and manual valves are often bigger than the lockshield valve, but this depends on the radiator model.

Sometimes it can be tricky to tell the lockshield valve apart from the other two by merely looking at them. If that is the case, here’s another way you can identify the valves. The thermostatic or manual valve is on the side of your radiator where hot water flows.

Knowing this, all you have to do when the heating comes on is touch the pipes on the radiator. The thermostatic or manual valve is the one that gets the hottest first.

With all of that out of the way, let’s now see how to turn a radiator off.

How to Turn Off a Radiator with a Thermostatic Valve

objects of home heating system brass valve, thermostatic valve, pipe cutter, copper plumbing parts

Turning off your radiator is pretty straightforward if it has a thermostatic valve. All you need to do is locate the valve with a numbered dial. It is usually on the bottom left side of most modern radiators.

Turn the thermostatic valve clockwise until it gets to the off position, setting it to 0 on the dial. The radiator is now turned off and won’t produce any heat.

Don’t worry about water in the pipes freezing because thermostatic radiator valves have a frost prevention mode. This feature allows a small amount of hot water to enter the radiator (even when turned off) to prevent freezing.

Although your radiator is turned off and mostly cold, you notice some hot water getting through into the appliance. This indicates that the frost prevention is working as it should.

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How to Turn Off a Radiator with a Manual Valve

If your radiator is fitted with a manual valve, it will be located on either the bottom right or bottom left of the appliance.

To turn the manual valve off:

  1. Locate the manual valve.
  2. Turn the valve clockwise as far as it will go.
  3. When the valve gets to the off position, turn it slightly counter-clockwise to open it a bit.

Why should you open the manual valve a little? Completely turning off a manual valve can cause the water inside the return pipes and radiator to freeze. If this happens, the pipes may rupture.

This is why it is important to let it a little bit of hot water, as it will prevent freezing, similar to the function of the frost prevention mode in thermostatic valves.

How to Turn Down Your Radiator

If your room is hotter than you like, but you don’t want to turn off the radiator, you can reduce the heat thrown out into your room by investing in a good-quality radiator cover. Well-designed radiator covers with reflective foil backing may even improve your heat efficiency.

If you don’t have a radiator cover, try covering the appliance with a blanket to reduce the heat. Don’t worry about burning the blanket, as the heat from the radiator won’t burn wool or cotton. However, do not cover your radiator with synthetic fabrics because the appliance can melt them.

You can also adjust the water flow from the boiler to your radiator if you don’t want to cover the radiator. By reducing the water flow through the pipes, the heat output will also reduce without necessarily turning off your radiator.

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How to Isolate a Radiator

Completely turning off your radiator may become necessary when you are renovating, carrying out maintenance, replacing a radiator, or fixing radiator leaks. You will need to turn the lockshield valve to the off position and also turn off the manual or thermostatic valve, depending on which one is on your radiator.

To isolate a radiator with a thermostatic valve:

  1. Turn the lockshield valve clockwise until it is fully open (make sure to note the number of turns as you will need to return it to the exact position later.
  2. Turn the thermostatic valve to the off position.
  3. Next, remove the head of the thermostatic valve and screw on the decorator’s cap that comes with your TRV. This will stop the frost protection mode from allowing hot water into the radiator, thereby isolating the appliance until you finish what you want to do.

To isolate a radiator with a manual valve:

  1. Turn the manual valve to the off position.
  2. Turn the lockshield valve to the right, making sure to note the number of turns (half-turn or quarter turn). You will need to return the valve to its exact position when you finish repairs, decoration, or whatever it is you want to do.

Note that whether your radiator comes with a manual or thermostatic valve, you may need to remove the cap on the lockshield valve to turn it.

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 4th February 2024

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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