You can empty a central heating system
You can empty a central heating system
A fully pumped gas central heating system can be flushed to enable work to be executed. To fit a thermostatic metal radiator valve or replace a failed metal radiator are two examples. Flushing your system is something that can be done by the none expert but competent do it yourself practitioner.
Whilst there can be a multitude of causes the most common is to flush the metal radiators. The first step you should take is to turn off the heating boiler and water heating pump. To enable the system to totally clear you will need to ensure that no water is getting in the central heating system.
The heating system has a header or expansion cylinder in the attic which will ensure that any water shortfall is topped up. A common ball-valve is used in the expansion cystern similar to that in a toilet. This ball valve is a ball attached to an arm that, when elevated closes the valve, which means when the water tank is full no more water can enter as the valve is closed. If water level falls the ball, floating on the surface, also falls venting the valve and allowing more water into the heating system. To fully flush the gas central heating system this top up process will need to be stopped. A good way to do this is to prevent the ball moving by splicing it to the top of the tank.
Once you have finished the above run a hose from an outdoors clean to the outlet of at the bottom of one of your heating radiators. Once you open the outlet valve the water will be able to current through the hosepipe to the outside clear. The hose should be attached to one of the lower heating radiators if you intend to flush the whole gas heating system. You now need to be diligent and check that all the water has emptied out and that no more water is entering before any other work is performed on the gas central heating system.
By opening the bleed valves in the radiators on the top level you will enable air to enter the gas heating system and hurry up the Draining process. When the water is flushed off you are free to work on your radiator.