Thermador induction zones that cut out mid-cook, Mandarin

Cooktops are shallow appliances with a lot going on underneath, and in this neighbourhood the thing underneath them is usually a drawer that was never supposed to be there. That single detail explains a large share of the induction faults we are called to.

Induction and heat

An induction cooktop is a power electronics box with a glass lid. The generator boards under each zone make heat of their own, and the appliance relies on a fan pulling room air through the cabinet to carry it away. The installation manual asks for a specific open area below and behind, and it is not decoration.

When the boards get too warm the cooktop protects itself. It reduces power first, then drops a zone, then shuts down entirely, and it usually does this at the worst moment, which is twenty minutes into cooking with a full pan on a high setting. Owners describe it as random. It is not random at all, and the tell is that it happens on long high-power cooking and never on a quick boil.

Mandarin kitchens make this common. Most of the housing here dates from the 1970s through the 1990s, and cooktops arrived later as a retrofit, dropped into a counter above a base cabinet that already had drawers in it. A drawer box under an induction cooktop closes off the airflow path the fan depends on. So does a stack of pans set into the cabinet, and so does a spice drawer insert fitted by a joiner who had no reason to know.

We check the temperature of the air leaving the fan before we quote a generator board. Where the cabinet is the fault we say so, because a new board in the same cabinet will fail the same way.

Pan detection

A cooktop that says it cannot find the pan is often telling the truth. Pans lose their magnetic base over time, particularly clad bases that have warped away from the glass in the middle. Before anything else, put a fridge magnet in the centre of the pan base and see whether it grips hard. If it does not, the appliance is right.

Where the pan is fine and the zone still refuses, the fault is in the coil or its driver, and that is a real repair with a real part.

Touch controls

Capacitive controls sit under the same glass as everything else and are affected by heat and by moisture. Controls that work cold and stop working after half an hour of cooking are a heat problem, which brings us back to the cabinet. Controls that stop working after a spill are usually a cleaning issue, and controls that never worked from cold are a control board.

Gas and electric cooktops

Gas cooktops fail the way gas burners always fail. Continuous clicking on one burner points at that burner’s electrode or a soaked cap; clicking on all of them at once points at the spark module. A burner that will not hold a low simmer is often a gas supply problem rather than a burner problem, and we measure pressure at the appliance before touching an orifice.

Radiant electric cooktops are simpler again. A zone that will not heat is a element, its relay, or the control that drives the relay, and those separate quickly with a meter.

Cracked glass

Glass is not repairable and we will not pretend otherwise. What we will do is tell you honestly whether a replacement surface is available for your model and what it costs against the value of the appliance, so the decision is yours with real numbers in front of you.

Every visit carries the same flat $80 diagnostic, credited toward the repair when you approve it, with ninety days on our labour and three hundred and sixty-five days on any part we install.