Venting the central heating system

Venting the central heating boiler and radiators

Venting the central heating boiler and the radiators is a chore we often forget. It is important though to do this at least once a year. When the heating system in your house is turned on, air builds up in the pipes of this system. If there is too much air, or the air stays in the system for too long, it could cause the pipes to rust. Furthermore, the air makes it harder for the radiators to heat up, which makes them use up more energy to get the desired result. Periodically venting your radiators and boiler is good for maintaining your heating system, and it could save you some money.

When is the time to vent

Venting your boiler and radiators should be done at least once a year. You should also do this when:

  • You notice your heating system starts to make strange noises
  • The radiators don’t heat up (enough) or slowly
  • The radiators start making ticking noises


To vent your boiler and radiators, you need:

  • A cloth, to catch up the water coming from the radiators
  • A vent wrench
  • Access to the thermostat and central heating boiler

How to

  • First of all, you should turn off the thermostat.
  • Then, you should also turn off the central heating boiler. You can do this, by disconnecting the plug from the socket. Wait 10 minutes, before you continue.
  • Open up all the radiators you would like to vent. We recommend you to vent all the radiators in your house, to make sure the air doesn’t move through your heating system. Start with the radiators on the ground floor, and work your way up.
  • Grab a cloth and place it under the radiator you want to vent. You’ll need this cloth to wipe up the water that will come from the valve. Take the vent wrench, open the valve, and wait for water to come out of the valve. You can close the valve again, once the air stops coming out.
  • Repeat this with all the radiators in your home.
  • Once you are done, you can switch the thermostat and central heating boiler back on.
  • You should check the water pressure of your boiler when you have finished venting the heating system. If the pressure is too low, less than 1.2 bar, you should refill the central heating boiler. Here is a manual on how the process works.

Here’s an instructional video on how to vent the boiler and radiators. Change the subtitles to English.

instructional video venting the central heating boiler and radiators

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