What is the acceptable level of oxygen in flue gases from gas appliances?

The acceptable level of oxygen in flue gases from gas appliances is crucial for ensuring efficient combustion and safety. An oxygen level of 3-9% in flue gases indicates that the appliance is functioning correctly, allowing for adequate combustion while minimizing the risk of incomplete combustion, which can lead to the formation of harmful carbon monoxide.

Maintaining oxygen within this range ensures that there is enough oxygen supply for complete combustion of the gas being used. If the oxygen levels fall below 3%, it suggests that the appliance might be experiencing insufficient air supply, which could result in incomplete combustion and dangerous byproducts. Conversely, excessively high oxygen levels beyond 9% can indicate that the appliance is over-firing or under-fueled, leading to inefficiencies.

Understanding these parameters helps plumbers and technicians assess the performance of gas appliances and ensures the safety and efficiency of heating systems. Thus, the range of 3-9% is recognized as the standard for acceptable oxygen levels in flue gases, as it balances reliable combustion with efficiency and safety.