Grill
Flashback: Flames Behind the Knobs or Under the Panel

What it
usually means.

Each gas burner is a tube that pulls air in at its front end, the venturi, mixes it with gas sprayed from the valve's orifice, and burns the mixture at ports along its length. When something blocks that path, most often a spider's web or an insect nest spun inside the tube during a quiet month, the mixture backs up and burns at the mouth of the tube instead, right behind the knobs and under the control panel. The same can happen when a burner is knocked off its orifice after cleaning, when rust closes the ports, when strong wind pushes flame backward, or when fat that pooled under the panel catches. The signs are a whooshing or roaring sound, flame visible in the gap below the knobs, a panel or knob hot to the touch, melted plastic, and often a lazy yellow flame at the burner ports at the same time. Flame there can burn the hose, the igniter wires and the valves themselves. Close the gas at the tank or the shutoff from a safe position, step back and let the flame burn itself out; do not reach for the knobs through heat, and do not relight until the burners and valves have been seen.