The knobs on the front of a La Cornue range are not the only point of gas control. A manual stop valve, separate from the oven thermostat knob itself, sits in the gas line feeding the oven, and it needs to be in the open position for the oven to ignite at all — a detail worth knowing both for everyday use and for ruling out a simple cause before assuming a bigger repair is needed.
What the Valve Actually Does
Where the thermostat knob controls temperature and turns the burner on and off during normal cooking, the manual stop valve is a separate, simpler on-or-off control for gas flow to the oven overall. La Cornue’s own instructions call for it to be left open, or “ON,” during normal use, and for it to be closed along with turning the thermostat knob to its off position whenever the oven will not be used for a while.
Why This Is Worth Checking First
An oven that will not ignite at all — no attempt at a spark, no smell of gas, nothing happening when the thermostat is turned up — is sometimes nothing more than a manual stop valve that was closed and never reopened, particularly after the oven has sat unused for an extended period, after a house move, or after any work was done nearby. Confirming the valve is actually open costs nothing and rules out one of the simplest possible explanations before assuming an ignition part has failed.
Restarting After an Extended Idle Period
La Cornue’s instructions also note that if the range has not been used for a long stretch, the ignition button may need to be pressed several times to clear trapped air from the gas line before the burner catches normally — this is expected after a long idle period and is not, on its own, a sign of a failing part.
Getting Into a Seasonal Habit
For a range used seasonally, such as at a vacation property, opening the valve and expecting a few extra ignition attempts on the first use of the season is worth planning for ahead of time, rather than assuming the range has developed a problem the moment it does not catch on the very first try.
Why Anything Beyond Opening It Is Technician Work
Confirming the valve is open is a reasonable check for any owner. Adjusting, repairing, or replacing the valve itself, or any other part of the gas line it sits in, is technician-only work, exactly as with any other gas connection on the range.
Safety First
If you ever smell gas while checking any of this, stop immediately, leave the controls exactly as they are, ventilate the room, and call from outside the house rather than continuing to investigate.
If your oven will not ignite at all, a La Cornue range repair visit checks the manual stop valve and gas supply before testing any ignition part.