How to repressurise your boiler
Re-pressurising a boiler may sound difficult and complicated; however, it is in fact quite a simple procedure to carry out.
Firstly, how do you know if your boiler needs re-pressurising?
If you have problems with your central heating, such as uneven heat distribution across your radiators or cold spots, first try bleeding your radiators. If the problems persist check the pressure on your boiler. To do so you just need to locate the pressure gauge on your boiler. Normally this should be between 1 and 2 bars of atmospheric pressure, if it is below this you will need to re-pressurise your boiler.
To re-pressurise your boiler, first make sure you locate the filling loop on your boiler. This is usually a silver or grey coloured hose with a small valve at each end. Some of these are internal whilst others are external. Either way it should have two valves which look like taps or have indentations in them.
Secondly, you will have to turn off your central heating and allow it to cool for approximately 30 minutes. Once the system is cool, check the valves on the filling loop are secure and then turn both of them either using the tap handles on them or with a flat-headed screwdriver if they do not have these.
Keep an eye on the pressure gauge on your boiler as you do this and as you turn the valves you should hear water filling the system. When the gauge reaches roughly 1.5 bars of atmospheric pressure then close the valves again. With this done you will have re-pressurised your boiler and can turn the heating back on. However, consult the manual of your particular boiler as some boilers need to be reset after re-pressuring them.