A way to flush a gas central heating system
A way to flush a gas central heating system
At some time in the lifetime of your fully pumped gas central heating system you will need to empty it. To exchange heating radiator valves or add an additional metal radiator as an example. This is often executed by the heating engineer during repair or extension work although some experienced homeowners have been known to clear their own gas central heating systems.
In most circumstances Flushing the central heating is executed to clean the heating radiators. Before any work is attempted you need to turn off the water heating pump and heating boiler. To enable the system to entirely clean you will need to check that no water is coming in the central heating system.
The gas central heating system has a header water tank in the attic which will ensure that any water shortfall is filled up. The expansion cystern uses a ballvalve similar to that in a toilet system. The ball floats on the water surface lifting a metal lever closing the valve when the water has reached the right level. Water is added to the heating system if the levels fall as the ball will drop on the water surface venting the valve. To ensure that the gas heating system fully empties we need to stop this mechanism. A good way to do this is to prevent the ball moving by tying it to the top of the water tank.
Once you have accomplished the above run a hose pipe from an outdoors empty to the outlet of at the bottom of one of your radiators. The central heating system can now empty by water flowing out of the radiator, through the outlet valve, and into the external empty. As there will be water in the ground floor radiators you will need to attach the hose to one of these to ensure that the whole central heating system drains. You must ensure before you start cleansing or replacing your radiator that all of the water has been drained out.
To make your central heating system drain faster you should open any bleed valves on your radiators, starting with the metal radiators on the top story and working your way down. When completed work can now begin on the system.