Power burners control the mixture of gas and air that is injected into the boiler's combustion chamber. These burners increase the efficiency of the boiler by providing an optimal ratio of gas to air.
A sealed combustion boiler pipes its air in from outdoors and delivers it to the boiler. The combustion gases thereafter are then piped back outdoors and are usually ÒpushedÓ mechanically by some type of blower. In other words, there is never a connection to the interior; it sends and receives air to and from the outdoors alone.