Which procedure should be followed to adjust the primary air on a burner?

The procedure for adjusting the primary air on a burner is crucial for achieving the correct combustion efficiency and ensuring safety in gas-fired equipment. When following the correct steps, it is necessary to first restrict the air supply by closing the air shutter until you observe a yellow flame. This indicates that there is not enough air mixing with the gas, resulting in incomplete combustion.

After identifying the yellow flame, you gradually open the air shutter again until the flame transitions to a steady blue color, which signifies that the gas and air are mixed adequately for optimal combustion. A blue flame indicates complete combustion, which minimizes the production of harmful byproducts like carbon monoxide and ensures the burner operates efficiently. Once the proper blue flame is achieved, the air shutter can be locked in place to maintain this setting.

This method not only helps in achieving the correct air-to-gas ratio but also enhances the overall performance and safety of gas appliances. Other options, like opening the air shutter fully or increasing gas pressure, may lead to inefficient combustion and potential safety hazards, while replacing the burner would be unnecessary if the adjustment can be made through the air shutter.