La Cornue Induction Zone Not Heating: What to Check Before You Book

You set a pan on a La Cornue induction zone, touch the control, and nothing happens. The display may light, the zone may beep or flash, yet the pan stays cold. That combination is more useful than it sounds, because induction cooking has very few moving parts and a cold zone usually falls into one of three groups: the cooktop does not see the pan, the cooktop sees the pan but is not allowed to power it, or the zone’s own electronics have failed.

Start with what the zone shows

Induction heats the cookware itself by passing a high-frequency field through the base of the pan, so the cooktop must first recognize a pan sitting over the coil. If the display shows a lone letter U, that is the pan-detection message: no pan was found or the pan is unsuitable. Our page on the U display message explains it in more detail, and the separate post on pan not detected walks through the cookware side.

If the display instead shows E, E2, Er followed by a number, or U400, the cooktop is reporting a condition rather than simply missing a pan. Write the exact characters down before you touch anything else. The library of meanings is short and specific: E is an electronic failure, E2 means the electronic unit is too hot and can also appear if a pan boiled dry, Er plus a number is an internal fault an owner cannot rectify, and U400 means the cooker is incorrectly connected. A hot-electronics message and a connection message point in very different directions, so the code saves a lot of guessing.

Likely causes, in plain language

• Cookware that induction cannot use. Pans with a base that does not respond to a magnetic field simply will not heat, and the zone will show the pan message or just sit idle.
• A pan that is too small, warped or off-centre. The cooktop needs enough of the base over the marked zone to recognize it. A badly warped base can lift away from the glass and confuse detection.
• Heat protection. After long, heavy use or an empty pan, the electronics can shut a zone down to protect themselves. Airflow around the cooktop matters here, especially in a tight custom installation.
• A supply problem. A tripped breaker, a loose connection after a remodel, or a circuit that was never sized properly for the whole cooktop can leave one zone, or all of them, without power.
• A failed component. The coil under the glass, the power board that drives it, or the control that sends the command can fail. These are brand-specific parts and need a technician and the full model and serial plate.

Safe checks you can do in order

1. Try the same pan on a different zone. If it heats there, the pan is fine and the first zone is the problem. If it fails everywhere, suspect the pan or the supply.
2. Try a different pan, ideally a flat-based one that you know works on induction, centred on the marked zone. A simple magnet test on the underside of the pan is a reasonable way to confirm it is suitable.
3. Wipe the glass and the base of the pan so there is no spilled sugar, film or water between them.
4. Check the breaker for the cooktop or range. If it has tripped, reset it once. If it trips again, leave it off.
5. Read and record any code on the display, then switch the cooktop off at the breaker for a short while and restore power once. One controlled reset is reasonable; repeated resets are not.

What not to do

Do not lift the glass, remove trim or open the cabinet beneath to look at wiring. Induction electronics hold energy and the supply is a dedicated high-capacity circuit. Do not switch the breaker on and off repeatedly hoping the zone will recover; each cycle stresses the power electronics and can turn a single failed component into a larger repair. And do not try a cold zone with an empty pan to see whether it warms, because a dry pan is exactly what triggers the overheating protection.

How installation changes the diagnosis

An induction module needs a properly sized dedicated circuit and clear ventilation underneath. In Bay Area homes where a range was moved during a kitchen remodel, we often find that the electrical work was done for a different appliance, or that a deep drawer or shelf now crowds the airflow path. A zone that works lightly and fails under heavy use points toward heat and airflow; a zone that never worked since the move points toward the connection. Either way, tell the technician when the symptom began and whether anything in the kitchen changed around then.

When to stop using the cooktop

Stop and switch off at the breaker if you see a burning smell, a crackling sound, a display that flickers or restarts by itself, glass that is cracked, or any zone that heats when nothing is on it. A zone that simply stays cold is an inconvenience, not a hazard, but the cooktop should not be left on and unattended while you troubleshoot it.

What to have ready when you book

Gather the model and serial plate details, the exact display message, which zone or zones are affected, the cookware you tried, and when it began. The plate on an induction range is usually behind a lower door or drawer or on the frame, and on a built-in module it is often under the front edge. Our guide to finding your La Cornue model number shows where to look. Induction coverage on this site spans the CornuFé lineup, including the CornuFé 110 and the CornuFé 90, and the induction hob modules used in the Château series.

What the visit looks like

A technician starts with the symptom and the code, checks the supply and the cookware recognition, and then isolates whether the coil, the power board or the control is at fault. You get a diagnosis before any repair, a written estimate, and nothing is done without your approval. For the full picture of how we handle these cooktops, see La Cornue induction cooktop repair and the overview of La Cornue induction cooktops.

Frequently asked questions