The location of the 14" passive roof vent in these
Burro 17s is on the same side as the gas range and just inboard of the stove hood. Add the intake fan and nothing as esoteric as positive or negative cabin pressure is required to depress the burner cones but merely a strong downdraft from the fan. A strong wind from the open door directly across the aisle from the cooktop is apparently also capable of deflecting the flame sufficient to overheat the porcelainized steel of the cooktop. I tend to think that exhausting air from the trailer cabin with closed doors and
windows would cause the negative cabin pressure which might draw smelly air from shower traps or badly fitting dump valves in some cheap RV toilets.
jack