Atmospheric and Pre Mix Burners
Gas appliances have traditionally used atmospheric burners to create a volatile gas/air mix to produce a clean and controlled burn at the burner head. The air gas mixture is ignited either by a permanent pilot or direct burner ignition. When hot water or central heating demand is called for the gas valve will allow the gas to pass to the main burner where it is ignited. Most modern appliances use electronic ignition (an electrode and automatic spark generator). The electrode discharges a spar directly onto the burner head and flame supervision is achieved through flame rectification or ionisation.
The air intake is open to the atmosphere within the combustion box therefore the burners, injectors and air intake could potentially become blocked which alters the air/gas mix consequently causing combustion problems such as flame vitiation and sooting. Regular servicing should prevent these issues occurring.