Every Château and CornuFé range uses the same basic burner design across its sizes: a brass burner engraved with La Cornue’s star pattern, sitting inside an enameled drip tray under an enamel-coated cast iron grate. On the larger Château sizes, the front burner is rated up to 17,000 BTU on natural gas and the rear burner up to 7,500 BTU, with a similarly-built power burner available at up to 22,000 BTU for oversized pans. All of them light the same way, and all of them fail to light for the same short list of reasons.
Turn It Off First
If a burner sparks continuously but the flame never catches, turn the knob off before doing anything else. Gas is being released while the knob is open and nothing is burning it, so switching it off is the first step, not an afterthought — leave the area to clear for a moment before continuing.
The Cap Is the Usual Cause
The single most common reason a La Cornue burner sparks without lighting is the burner cap sitting slightly off-square on the crown, usually after cleaning. The cap has to sit flat so the spark can reach the gas at the right point; lifted even slightly on one side, the spark discharges into open air instead. Reseating the cap correctly resolves a large share of these calls without any part being replaced at all.
When It Is Not the Cap
If the cap is seated correctly and the burner still will not catch, the next checks are the igniter itself — whether it is producing a spark at all, and whether that spark is reaching the burner reliably — and gas flow to that specific burner, since each burner on a multi-burner Château hob is fed and controlled independently. A burner that fails intermittently rather than every time often points at a loose or corroded igniter connection rather than the igniter unit itself.
The French Top and Power Burner Are the Same Family
The French top plaque and the power burner use the same style of ignition as the twin burners, so a French top that will not light is diagnosed the same way: cap and crown seating first, then the igniter, then gas supply. Because the French top’s single burner heats the entire cast iron surface rather than a single ring, a problem here is noticed as “nothing on the plaque is getting hot” rather than one localized cold spot.
What This Is Not
A burner that lights fine but then goes out again after a few minutes is a different problem — a worn safety thermocouple rather than an ignition problem — and is covered separately, since the two signs point at different parts and different repairs.
If a burner will not catch after checking the cap yourself, a La Cornue range repair visit tests the igniter and gas supply at that specific burner before anything is replaced.