Bleeding a radiator

Job description:

Bleeding a radiator is a task easy to achieve, but which should not be neglected. An overflow of air is harmful, because it causes unpleasant noises in the radiators and can block the flow of water. In extreme cases, water is not flowing through the radiator which stays cold while the heating circuit is in operation.

You can bleed your radiators at the beginning and at the end of the winter or in emergency, when you hear sounds of water in the radiators.

Skill level: 1 – Beginner

Materials required:

  • Key
  • Screwdriver
  • Small recipient
Step by step guide to bleeding your radiator:

1. The central heating must be stopped. This means that the pump (pump of the boiler) should no longer work. The easiest way is to adjust the boiler set to 'summer '. The ideal is to wait until the radiators are cold. Otherwise, act with caution in order not to get burnt.

2. At the top of the radiator, there is a valve, single or provided with thermostatic adjustment. The bleed screw is located at the other end. Depending on the model, it is a knob brass or some kind of head bolt hollow hexagonal. To manipulate the wheel type one, a pair of pliers is sufficient. For the bolt one , you will need a special butterfly key.

3. Bleed the radiator in order to expel the air.

4. Place a container under the screw.

5. Unlock it by a quarter turn, then very slowly until you hear a hissing sound very distinctly. After a few moments, the trap also spits water. Wait a few seconds and then close it.

6. Simply tighten it by hand, without forcing it, as you would for a standard tap. If there is a small drop of water after the closure, it has no importance. On the other hand, if the flow is continuous, if you must force to stop it, talk to your plumber.

7. Partially emptying the central heating system means that the pressure has dropped in the circuit. It is therefore necessary to restore it by adding water. The filling valve is most often located underneath the boiler. Open it carefully and watch the pressure gauge on the control panel of the boiler. Stop filling and close the valve as soon as the needle reaches 1 bar.

8. Allow the water to drain. This water can be grey: this is normal. It contains in part the radiator sludge. You have finished to drain the radiator when the stream of water is regular. Indeed as long as it comes out so fickle, your radiator still contains air.

9. Tighten carefully and firmly each screw of each radiators before replacing your water supply system . Check that the screw is dry. Do the same for all the radiators in your home. Replace the valves at a more normal temperature.

If you have to repeat this operation several times during the same period of heating, you should suspect a leak somewhere.

Unless you are good at DIY, you might want to contact a local heating specialist.

The information provided in this guide is to be used strictly for guidance only. We recommend you always read the manufacturer's instructions.