CO is produced by incomplete combustion in a heater or boiler. As burning fuel is starved of air it generates higher levels of CO, this is due to there being insufficient oxygen to produce carbon dioxide (CO2). CO2 is produced when carbon in fuel is fully burnt and all the heat released. With a shortage of oxygen the carbon does not fully burn and produces Carbon Monoxide (CO).

In a domestic boiler, CO can be produced by the following problems:

• Blocked flue not allowing the products to escape.

• Inadequate air supply causing a shortage of oxygen.

• Flue products entering the air supply and causing a shortage of oxygen.

• Worn burner parts causing incomplete combustion of fuel.

Any of the above causes, linked to conditions where CO can enter a room, is a recipe for disaster or ultimately.........

.........DEATH!