Blichmann Burner Flame Escaping

I posted a brief note about this when reviewing my Tower of Power, but I figured I'd come looking for answers with a specific post.

While testing my system today, the flame from the burner jumped into the area right behind the air damper. It happened twice, once upon ignition and once when the gas was cut by the valve. I am guessing that this means gas is leaking into this area, but I am not sure why this is happening. The appropriate connections are sealed with yellow teflon and tightened and I keep the gas turned down pretty low.

Anyone have any knowledge as to what causes this? Too much gas, not enough air, something else?

Are you saying the flame was inside the venturi bell behind the air damper?

I could see this happening immediately after the gas is shut off, but it would only last for a moment. I've often heard one or the other of my Blichmann burners "pop" within a few seconds of turning off the gas supply and I've always assumed it was the residual gas inside the burner cavity igniting (I've never actually seen what happens when they "pop" like that).

Happening on turn-on is a bit more disconcerting and harder to understand, unless there is insufficient gas flow at the leading-edge of turn-on...

Cheers!

I didn't know what that part of the burner was called, but yes flame inside the venturi bell. When it happened during flame cut out the flame stayed long enough for me to notice and worry (3-4 seconds maybe). When it occurred on ignition is went out quickly.

I've seen this on non-Blichmann systems when there isn't enough air flow escaping under the kettle. Without enough air flow, all the fuel doesn't combust and it eventually ends up shooting flames out the venturi opening. Doesn't the Blichmann has adjustable pads where the kettle sits? I'd try getting a little more space between the top of the burner and the bottom of the kettle.