You will need:

• Adjustable spanner
  Stillson wrench
  Small pot to catch water
  Large bucket
  Dry cloths
  Gloves
  Radiator bleeding key

Step 1: Release trapped air

If the bottom half of your radiator is hot, while the top stays cool, you may have a problem with trapped air.

Use the key to open the bleeding valve (the valve at the top of the radiator).

Once the valve is open the radiator should start hissing, letting air out. You’ll be able to feel the water rising to the top of the radiator if your heat is on. Hold a cloth to the bleeding valve as it will start to leak water when the radiator is full. When this happens, close the valve.

Tip: If you have other rads in the house that don’t heat up at all, there could be a problem with the pump or system. Call a plumber!

Step 3: Remove the radiator

Get someone to help you lift the radiator. Lift it up from the wall brackets and turn it upside down to prevent water and dirt from spilling out.

Carry it out into the garden upside down.

Still upside down, hold a garden hose onto the open valve at one end and turn on the tap. Let the water fill the radiator and then flush through and out the other valve.Let the water run through the radiator until it comes out clean at the other end.

Turn off the hose and tip the radiator to let the rest of the water and gunk pour out.

Step 4: Replace the radiator

Put the radiator back into place.

Tighten all valves (they only need to be finger tight plus a half turn with the wrench).

Open the bleeder valve and let the radiator fill with water.

Shut the bleeder valve.

Tip: You can add scale inhibitor to your system to prevent gunk build-up. If you have an old boiler, put the inhibitor into the tank in your loft. If you have a combi system, you’ll need to push the inhibitor into the radiator itself.

via: uktv.co.uk