Brass radiator standard bleed key for essential central heating maintenance.

All radiators can collect air if there is any air in your system, even air which is released from solution in the top-up tank water.

If there is  a temperature step at some level in your radiator, then the first thing you need to do is bleed the radiator. Take care not to allow air to flow into the radiator. Usually there is a head of water in the system, or a back pressure and if the heating is running there is a positive pressure and this is the best situation.

The radiator must be below the header tank if your heating is turned off, but if your heating is on, there should be pressure from your pump to allow bleeding to take place, but do check as the sound of air going in is extremely similar to the sound of air coming out :-).

Some radiators need to be bled for air locks on a regular basis to keep the home central heating system working properly - this may need to be done once per month at first, but if there is no air being exhausted this can be extended to suit (I do mine bi-annually).

In the winter months this can make a significant contribution to the efficiency of your heating system.

Notice that not all bleed screws have the same sized square head. This key fits over a 5mm screw and is the most common size but there areother sizes too.