What usually causes a noisy, lifting, blowing pilot flame?

A noisy, lifting, blowing pilot flame is primarily caused by the conditions surrounding the flow of gas to the pilot burner. When there is excessive gas supplied to the main burner, this can create a turbulence that affects the pilot flame, leading to instability in its operation. The increased flow of gas can result in a pilot flame that appears lifted and noisy as it struggles to maintain a steady combustion process due to the disruption created by the excess gas.

The stability of the pilot flame is crucial for the proper operation of the burner, and any irregularities in this flow can lead to a variety of symptoms, including the blowing effect. Maintaining the correct gas pressure and flow rates is essential for the proper functioning of both the main burner and the pilot flame in ensuring safe and efficient combustion.