If you hear a lot of banging coming from your boiler or heating system, you may need to perform a little repair. The banging could be the result of not enough water in your system, but it could also mean there is too much air in your expansion tank. And expansion tank is attached to your boiler and helps regulate the air to water ratio for optimum performance. If the air in your expansion tank expands too much, you may need to release some of the air in order to use your tanks properly and stop the banging noise.
This tutorial from the DIY guy will show you exactly how to remove air from your boiler or heater. This tutorial will take you step by step through this relatively simple process and save you the headaches and expense of having to call a professional or worse..replace your tanks.