Last updated on January 29th, 2024
Turning a radiator off can sometimes cause problems, especially on old heating systems with radiator valves that haven’t been touched for many years.
They can start leaking and break when using them for the first time.
I have been repairing and replacing radiators for over a decade and I have turned off and on all types of radiator valves many times.
Here I’ll show you how to turn off a radiator based on my everyday experiences over the years.
How to Turn off a Radiator
To turn off a radiator you must close one of the valves at either side of the radiator. You can close any of the two valves to turn it off or you can close both valves if you want to remove the radiator.
Having a good pair of water pump pliers are best for turning lockshield valves as it’s much quicker and easier than using an adjustable spanner (once you get used to using them).
Water pump pliers can also grab rounded-off valves or even manual plastic handles when they are too stiff to turn with your hand.
Thermostatic Radiator Valve
To turn a radiator off with a thermostatic valve you must turn it clockwise until it’s on ‘off’ or ‘0’.
You can also turn it to frost setting (if you have one) which means the radiator will stay off unless the temperature drops to below 5 degrees in that room.
Without Thermostatic Valve
Turning off a radiator without a thermostatic valve means you’ll need to close either the lockshield valve or the manual valve.
Manual Valve
With a manual valve, you need to turn it clockwise with your hand as far as it will go. You might need to start it off by using some water pump pliers as they can be tight when they haven’t been turned for years.
Lockshield
For lockshield valves, you must remove the radiator valve cap and then turn the valve clockwise with an adjustable spanner, some water pump pliers or some valves will need an hex key to close it.
You should be able to pull the lockshield valve cap off or screw it off with your hand but if there’s a screw in the middle, then you’ll need to remove the screw first with a screwdriver.
How to Turn off a Radiator When it Leaks
When a radiator leaks you should isolate it from the central heating system by closing both of the radiator valves. This will cut off the water supply to the radiator.
The leak should stop when the pressure inside the radiator drops (which could take a while).
If it doesn’t stop leaking then one of the valves might not be closed fully or damaged which means you’ll have to replace the radiator valve.
How to Turn Down a Radiator
You might just want to turn down the temperature of a radiator instead of turning it off.
Here are a few ways:
At The Boiler
To turn the temperature of a radiator down you can turn the heating/radiator dial on the boiler down, but this will turn down all of the radiators.
Thermostatic Valves
You can also turn the thermostatic radiator valve down to a lower setting but the temperature of the radiator will remain the same as before.
The radiator will turn off when the temperature of the room has reached what the thermostatic valve is set to.
Lockshields
The best way to turn a radiator down properly is to partially close a lockshield radiator valve. This is how to balance radiators.
You must turn the valve clockwise as far as it will turn and close it using some water pump pliers or an adjustable spanner. Then open it a quarter turn, keep opening it slightly until it’s at the temperature you want.
How to Turn off Towel Radiator
Turning off a towel radiator is usually easy as they mostly have manual valves.
You can turn either one of the valves clockwise as far as it will turn. You might need to use some water pump pliers to get it going.
How to Check Radiator Valves Are Open
One radiator not working is sometimes caused by the valve being closed without knowing that it’s closed.
To check radiator valves are open you need to turn the valves anti-clockwise as far as possible.
If the radiator valve does not turn anti-clockwise then try turning it clockwise to see if it’s moving.
If it doesn’t move either way then it must be stuck and you’ll need to force it to free it. The best way is with a decent pair of water pump pliers.
Summary
Turning a radiator off is very simple most of the time, especially if you have thermostatic radiator valves.
Just remember to turn any valves clockwise to turn them off and anti-clockwise to turn them on.
There are times when turning off a radiator goes bad like when it causes a radiator valve to leak because it hasn’t been touched for so long. In which case you’ll need to replace the valve.
Feel free to ask me any questions in the comment section below and I’ll try my best to help.
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FAQs
What are the two valves on a radiator for?
The two valves on a radiator are for turning the radiator off or controlling the temperature of the radiator with a manual/lockshield valve or the room with a thermostatic valve.
Which way to turn the radiator off?
You must turn a radiator valve clockwise to turn it off and anti-clockwise to turn it on.
Is a leaking radiator dangerous?
No, a leaking radiator is not dangerous for the most part but it could cause quite a lot of water damage to flooring or anything below the leaking radiator including electrics.
Really appreciate the clear instruction and explanation on this page Steven. I’ve just had a radiator leak on my Lockshield valve and you’ve saved me a lot of trouble before I can get a plumber into to replace parts. Thank you very much!
Hi Steven, When my heat is on high about 27 all radiators are hot if I turn it down to about 19 the last 4 in the system won’t heat up why.
Hi David,
That’s a strange one. I’m assuming it’s a large system. The only thing I can think of is it takes a long time to heat up the full system properly so by the time the heat has reached the last radiators, the room which the thermostat is in has already reached 19 degrees so it cuts the boiler out.