Burner puffs fireballs when turned off

[treaves]

I have three of the low pressure burners from HURRICANE LOW PRESSURE BURNER (NO STAND) @ Williams Brewing

I am testing them out now. These are fed through Honeywell valves, and use a standing pilot. The one I use for hash exhibts this problem: when the power is turned off to cut the propane supply, the flame goes down, then there is this big poof of a flame ball. Then it's out.

Any ideas how to stop this?

Thanks.

 

[SilverZero]

That happens on my back porch grill all the time. Never really worry about it, I thought it was normal (or just not uncommon).

 

[kladue]

The "Puff" is normal, the longer the tubing between the valve and the burner, the larger the puff will be as the gas flow stops and flame flashes back inside the burner. Adjusting the air shutter to the least excess air setting (flames have slight yellow in tips) helps tone it down a bit.