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How To Drain A Radiator

There are a number of reasons why you might want to drain your radiator. It may be full of sludge so you need to clear it out, you might want to remove it for painting or simply replace it with a new one. Whatever the reason, we've created this guide to take you through the process quickly and safely.

You Will Need:

  • Adjustable spanner
  • Grips
  • 2 Containers to catch water
  • Old towels

How To Drain A Radiator:

  1. Turn off your heating
  2. Close the thermostatic valve
  3. Close the lockshield valve
  4. Remove the TRV nut
  5. Open the bleed valve
  6. Remove the lockshield valve nut

1. Turn Off Your Heating

Before working with your radiators, you'll need to completely switch off your heating system and allow it to cool down for at least an hour. When you're draining the radiator, you don't want to get scalded by any water so this is an important step.

turning off heating

2. Close The Thermostatic Valve

Once your heating system has been switched off and has cooled down, you'll need to close the thermostatic radiator valve (TRV). You can do this by turning it to zero.

turning off the TRV]

3. Close The Lockshield Valve

You can now move across to the other side of your radiator and close the lockshield valve. First, remove the plastic cap. Then take your grips and turn the valve clockwise. Pay close attention to how many times you turn the valve and note this down. This will help your radiators stay balanced when you reconnect it or add a new one.


4. Loosen the TRV Nut

Now you've turned off both valves, you can begin to disconnect the radiator. First lay down your old towels around the valve and place a large plastic container underneath to catch the water.

Starting with the TRV, use your grips to hold the body of the valve and use your adjustable spanner to loosen the nut that connects the valve to the radiator. As you disconnect the valve, water will begin to flow out so make sure your containers are ready. 

Once you've loosened the nut, take your radiator bleed key and open up the bleed valve. This will let air into the radiator to help the water flow out.


5. Loosen The Locksheild Valve Nut

You can now place another container under the lockshield valve. Grab the body of the valve with your grips and loosen the nut with your adjustable spanner.

With both valves now open, you can completely loosen the nuts and lift your radiator to one side to let the remaining water drain out. If all went well you should have successfully drained your radiator!

Once you've drained your radiator, there are a number of other steps you might want to take:

Removing Sludge From Radiators

In this blog post we show you how you can remove the sludge clogging up your radiators to keep them working at their best.

Replacing a Radiator

If you've removed your radiator this guide will show you how you can easily replace it with a new one.

Painting Your Radiator

If you've drained your radiator because you want to remove it and paint it, take a look at this guide.

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