If your radiators have not heated up properly and you can feel a patch of cold to the top of the unit it’s more than likely that you have trapped air in the system which needs releasing so the water can flow around the pipes uninhibited.
Trapped air in a central heating system is not a good thing as it can cause the following issues:
Before you get started you need to know what kind of heating system you have:
If you are not sure which heating system you have have a look in your loft space – if you have a header or expansion tank then your system is open vented, if not you have a sealed system.
Bleeding radiators with an open vented system is quite simple as it means the water will automatically be added to the system when you bleed out the air. A sealed system has an expansion vessel (rather than a tank), a pressure gauge and a filling loop. The loop will refill the system with water once you have bled the radiators.
We recommend you only bleed the radiators on a sealed system when they are cold so you can obtain an accurate pressure reading on the pressure gauge.
You will also need the following tools:
Step by step
Now you know what kind of system you have and you are ready with your tools, we can get started:
Go to the radiator which requires attention and locate the bleed vent. The vent is generally on the top corner of one side on your radiator.
Insert your radiator key and turn it anti clockwise to gently open the bleed vent. (Be careful if the bleed vent is stiff. They are made of brass and you can easily round off the end or snap it if you are too heavy handed.) You will start to hear a hissing sound as the air escapes. Hold your cloth just under the vent as you do this.
When water seeps out of the bleed vent gently close it until the water stops. The water may be dirty so be sure to have your cloth ready to catch any trickles that run down.
For a sealed system
You will need to check the pressure by looking at the pressure gauge generally located on the front of the boiler or on the expansion vessel if a separate one is fitted. Typically your heating system will be set between 1 and 1.2bar. If it’s dropped below this you will need to turn the filling loop on. You will either have one black handle at one end, or two black handles at either end of the filling loop*. Turn the handle (or handles) just a quarter of a turn so they are inline with the loop, this will let the water in. Always turn the filling loop slowly as you are only topping up the system. Remember, this is mains water pressure so water will enter the system quickly if you fully open the valve(s). When the pressure reaches this level turn the filling loop off and check the needle on the gauge has stabilised. Now you are ready to turn your boiler back on.
If you need help with you boiler or heating system contact Property-Serv today. We have a team of expert heating and boiler repair engineers in Liverpool ready to help.