A La Cornue range runs several separate gas-fed parts — two brass burners, a French top plaque, an optional power burner, and on some configurations a lava-rock grill or a Flamberge rôtisserie burner — each with its own valve and its own connection. That is useful to know for ordinary troubleshooting, but it is not the first thing to think about if you can actually smell gas.
The Sequence, In Order
If you smell gas near the range, leave every knob and switch exactly where it is. Do not turn a burner off, do not turn a burner on to “see if that’s it,” and do not operate any electrical switch near the appliance, including a light switch in the same room — a spark from a switch is a genuine ignition source in a room where gas has accumulated. Open windows and doors to ventilate. Leave the house. Call for help from outside it, whether that is your gas utility’s emergency line or ours.
Why the Order Matters
Each of those steps exists because the alternative carries a real risk, not a theoretical one. Touching a switch could ignite accumulated gas. Turning a knob to “check” releases more gas if the valve was already leaking, or disturbs a problem in a way that makes it harder to find afterward. Ventilating before you leave, rather than instead of leaving, reduces concentration in the room without requiring you to stay in it.
What Happens Once It Is Safe
Once the property has been confirmed safe, gas connection work on a La Cornue is technician-only. That covers the range’s own internal gas lines, its connection to the household supply, and any conversion between natural gas and propane, which requires refitting the correct orifice at every gas-fed part — the two brass burners, the French top, the power burner, and the grill where fitted — not just adjusting a valve. Each burner on a Château or CornuFé range has a published BTU rating for both natural gas and propane, and the difference between those ratings is exactly why an orifice sized for the wrong fuel produces the yellow, uneven flame and poor simmer that people often mistake for a worn burner.
What Is Not an Emergency
It is worth separating a genuine gas smell from the ordinary quirks of a range this specialized: a burner that clicks and sparks but does not catch, without any smell, is very often a burner cap seated slightly off-square rather than a leak, and it is a booking rather than something to act on urgently. The distinction is the smell itself — if you cannot smell gas, you are looking at a repair; if you can, you are looking at the sequence above.
For everything short of an active gas smell, a La Cornue range repair visit is the right next step, and gas conversion or connection work is always carried out by a technician rather than attempted at home.