--- title: "Burner will not stay lit" description: "La Cornue burner will not stay lit — a burner that lights while the knob is held and dies when it is released is a flame supervision failure, and it" url: "https://la-cornuemiami.support/symptoms/burner-will-not-stay-lit/" date_modified: "2026-09-03" Appliance type: "Cooktops and rangetops, Ovens, Ranges, Rangetops" --- # La Cornue burner will not stay lit ### How long does it hold? Time it. A burner that dies the instant the knob is released has almost no supervision signal at all — a failed thermocouple, or one that has been knocked out of the flame. One that holds for five or ten seconds and then drops is a weak signal or a tired valve magnet, which is a slightly different repair. And a burner that stays lit for minutes and then goes out during cooking is neither: look at whether a pan is covering the burner completely or a hood on high is pulling the flame about. ### What it usually means, by the kind of La Cornue appliance La Cornue sells one appliance in several forms, and the same behavior points at different things on each of them. A built-in side-by-side and an integrated column are not the same service situation, and a dual-fuel range and an induction range fail in different halves. - **Château gas oven** — The vaulted gas oven has no display to explain itself. Lights, dies, no code — that is normal behavior for this make and it points straight at supervision. - **Château and CornuFé surface burners** — Same principle, smaller parts, and reachable from the front without moving the range. - **All-induction and Tourelle** — No gas, no flame supervision. Nothing here applies. ### Why the oven version is urgent and the cooktop version is not A surface burner that will not stay lit puts its gas into an open room above a visible flame, and you know immediately whether it is burning. A vaulted gas oven has no window, sits behind a heavy insulated door, and holds whatever it is given. An oven that lights and dies, tried three or four times, is a sealed cavity with an unburnt charge in it — which is why we treat this as a same-day call on the oven and a normal booking on the cooktop, and why the honest advice is to stop trying and shut the range off at its valve. ### What the repair looks like The thermocouple’s output is measured against what the valve needs to stay energised, the valve is held open and released to see whether it creeps, and on an oven the igniter’s current draw is measured rather than judged by how brightly it glows. All three parts are reached from the front. Then the appliance is run through a full cycle in front of us, because a burner that holds once and fails on the second attempt is the commonest trap on this problem. A failed or displaced thermocouple The sensor that tells the valve there is a flame. Most of these calls end here. A weak safety valve magnet It holds for a few seconds and lets go. Measured rather than guessed. A dirty or soot-coated sensor tip It is in the flame and it no longer conducts. Cleanable sometimes, replaceable always. An oven igniter too weak to open the valve The classic vaulted-oven failure: it glows, and it never reaches the current the valve needs. Draft or a covered burner Not a problem. A hood on full or a pan sealing the crown can put a burner out. Count the seconds Instantly, or after five to ten. Two different parts. Try it with the hood off A hood on high can lift a low flame off a surface burner. Free to rule out. Try another burner If every burner does it, the supply or the manifold is involved. Stop after two attempts Especially in the oven. Repeatedly filling a cold vaulted cavity with gas is the one thing not to do while waiting. It lights and then goes out What it usually means The safety chain is working — it just no longer sees the flame Thermocouple, then valve, in that order An oven that does this is a same-day call How long does it hold? Time it. A burner that dies the instant the knob is released has almost no supervision signal at all — a failed thermocouple, or one that has been knocked out of the flame. One that holds for five or ten seconds and then drops is a weak signal or a tired valve magnet, which is a slightly different repair. And a burner that stays lit for minutes and then goes out during cooking is neither: look at whether a pan is covering the burner completely or a hood on high is pulling the flame about. What it usually means, by the kind of La Cornue appliance La Cornue sells one appliance in several forms, and the same behavior points at different things on each of them. A built-in side-by-side and an integrated column are not the same service situation, and a dual-fuel range and an induction range fail in different halves. Château gas oven — The vaulted gas oven has no display to explain itself. Lights, dies, no code — that is normal behavior for this make and it points straight at supervision. Château and CornuFé surface burners — Same principle, smaller parts, and reachable from the front without moving the range. All-induction and Tourelle — No gas, no flame supervision. Nothing here applies. Why the oven version is urgent and the cooktop version is not A surface burner that will not stay lit puts its gas into an open room above a visible flame, and you know immediately whether it is burning. A vaulted gas oven has no window, sits behind a heavy insulated door, and holds whatever it is given. An oven that lights and dies, tried three or four times, is a sealed cavity with an unburnt charge in it — which is why we treat this as a same-day call on the oven and a normal booking on the cooktop, and why the honest advice is to stop trying and shut the range off at its valve. What the repair looks like The thermocouple’s output is measured against what the valve needs to stay energised, the valve is held open and released to see whether it creeps, and on an oven the igniter’s current draw is measured rather than judged by how brightly it glows. All three parts are reached from the front. Then the appliance is run through a full cycle in front of us, because a burner that holds once and fails on the second attempt is the commonest trap on this problem. ### It only does it when the range is already hot. That is a useful and specific clue. Heat changes clearances and resistances, and a marginal thermocouple or a tired valve magnet will hold from cold and let go once everything around it has expanded. It is still the same repair — the parts are the parts — but it tells the technician to test hot rather than cold, which is exactly the test that gets skipped. Say it when you book. ### Is it safe to keep using the other burners? Yes, if they light and hold normally, and if you can smell nothing. The safety system is per burner. What we would not do is keep using the oven, and we would not leave the range unattended while a marginal burner is lit — a flame that has been going out is a flame that may go out again with a pan on it. --- **[Read full article: Burner will not stay lit](https://la-cornuemiami.support/symptoms/burner-will-not-stay-lit/)**