Unstable flame and vibrations in the burner: causes and diagnosis

Unstable flame, pulsations, or vibrations in the burner may stem from an improper air-gas ratio, draft, gas pressure, or mechanical instability.

Gas pressure

Pressure fluctuations or regulator hunting can cause periodic variations in the flame.

Combustion air

A servomotor, damper, or fan that does not follow the command consistently can create oscillations.

Chimney and combustion chamber

Incorrect draft or resonance phenomena can amplify pressure fluctuations.

Burner head

Wear, contamination, or incorrect adjustment of the burner head can affect flame distribution.

Diagnosis with trends

Simultaneous recording of gas pressure, damper position, load, and flame signal helps determine if the cause is combustion, adjustment, or mechanical instability.