Thermador Induction Error in Unionville

The call

A Unionville kitchen with a Thermador Freedom Induction cooktop — the full-surface design where pans can sit anywhere rather than on marked zones. The left half had stopped responding entirely. The right half worked normally.

The owner had already been told by another company that the glass surface would need replacing, and had been quoted accordingly. On a cooktop of this class that is a serious number, and they wanted a second opinion before committing.

They were right to ask. The glass was undamaged — no crack, no chip, no impact mark anywhere on the surface. Glass that is intact is almost never the reason a zone stops working.

Diagnosis

Freedom Induction surfaces are driven by several independent power modules, each responsible for part of the cooking area. That architecture is the key to diagnosing them: one module failing takes out a whole region while everything else behaves normally, which is precisely what the owner described.

Working through it:

• Glass surface intact, no damage on either face
• Touch controls responsive across the full panel, including the dead area
• Cookware confirmed induction-compatible — it worked on the right side
• Cooling fans running, airflow path clear beneath the unit
• Supply voltage correct at the terminal block
• Left-side power module: no output, while the right-side module tested normally

The fault memory backed it up, logging repeated faults on the left channels and nothing on the right. The controls were talking; the module was not answering.

The fix

Left-side power module replaced with the Thermador factory part. This is one of the components where a substitute genuinely does not work: modules are matched to the surface configuration and to each other, and fitting one from a different variant produces zones that run at the wrong power levels or drop out under load — behaviour that reads as a failing cooktop rather than a mismatched part.

While the unit was open we cleaned the cooling path and checked the fan, because heat is what kills these modules. In a fitted kitchen the drawer beneath frequently blocks the airflow the electronics depend on, and we mentioned that to the owner with a recommendation about what to keep in it.

Then every zone tested individually at multiple power levels, plus a sustained high-power test on the repaired side to confirm it held under thermal load. Ninety minutes.

Outcome

Full surface working, and no glass replacement.

Someone else told me the whole cooktop was finished. This cost a fraction of that and took an afternoon.

The general point: on a multi-zone induction surface, a dead area is a module, not the appliance. Identifying which module keeps the repair proportionate. Replacing the glass, or the unit, when a single component has failed is an expensive misdiagnosis — and on a full-surface design like this one it is an easy mistake to make, because the failure looks dramatic.

Worth knowing too: if an induction cooktop shuts down mid-cook and recovers later, that is usually heat rather than failure. Airflow under the unit matters more than most owners are ever told.

Total: $395 before HST, covered by our 60-day parts and labour warranty.