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Guide On How To Bleed A Radiator

Sometimes a radiator can clunk and bang as it begins to warm up, other times it can remain cold long after you’ve turned your heating on. If this is the case, you may need to bleed your radiators.

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Radiators need bleeding when pockets of air get trapped inside. The air causes the radiator to circulate hot water less effectively and so less heat is emitted, meaning it will take longer to heat your home. Until you bleed your radiator to get rid of the air, you’re likely to be using more energy and therefore your energy bill could be higher than average.

Follow these steps to check and bleed your radiators:

  1. Put your central heating onto full and wait for your radiators to reach their maximum heat.
  2. Being careful not to burn your hands, feel along the top of each radiator for any cold areas. Cold spots are an indicator of trapped air, and so you’ll need to bleed any radiators on which you do find them.
  3. Before you bleed your radiators, ensure your heating is turned off and your radiators have completely cooled.
  4. Although a screwdriver can be used for some modern radiators, most radiators require a radiator key to bleed. If you don’t have a radiator key, you can pick one up from most DIY stores.
  5. Ensure you have a cloth below the radiator valve to catch any water.
  6. Holding the key with a cloth, slowly turn anti-clockwise to open your radiator’s valve. You should hear a hissing sound as the air escapes.
  7. Wait until the sound stops and water starts to leak out before turning the key clockwise to close the valve.
  8. Once all your radiators have been bled, check the pressure of your boiler gauge. If the pressure is too low, you’ll need to rebalance the pressure. If the pressure is normal, you can switch your heating on and check that there aren’t still any cold areas.

We recommend doing a full check of all the radiators in your home every couple of months.

Video Transcript

How to Bleed a Radiator

If you find one or more of your radiators is hot at the bottom, cold at the top, or even cold all over — this means you will need to bleed your radiator.

For this you need a bleeding key. You can buy these from you local hardware store.

At one end of your radiator there is a slot that the key fits into.

Make sure you have a cloth underneath before turning the key.

When you turn the key, you will hear a hissing noise — this means that the built up air in the radiator is releasing.

As soon as water starts to come out and the hissing stops — close it and wipe up any excess water.

Do all of your radiators starting from the ground floor up.

Check your boiler after bleeding all the radiators in case your pressure has dropped as the pressure may need topping up. You can refer to our re-pressurising video. If its a combi or pressurised system — you will need to re charge the system using the filling or link key ensuring the correct pressure is added

If the pressure drops again, the radiators may need topping up and you may need to call a Help-Link engineer. Visit help link dot co dot uk for more details

Defrost a frozen condensate pipe

You can identify if you have a problem with your boiler’s condensate pipe by checking if the blue light on the front of the boiler is flashing.

The blue light is located in the small window gap on the front of the boiler flap.

Ensure the power to the system is switched off.

Located in the top right hand corner underneath the flap is a digital window, this may be flashing up the letters EA.

This either means that there is no gas getting into the system or condensation isn’t getting out. If its mid winter this usually means a frozen pipe.

Locate the pipe outside.

To cure the frozen pipe, simply get a kettle of hot water (not boiling) and put this evenly along the pipes — paying special attention to the joints.

Alternatively you can tuck a hot water bottle around the external pipes and leave it for half an hour.

If this doesn’t do the trick, we recommend you call one of our experts to help you fix the problem.

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