Mark Hensley
Senior Appliance Editor · Induction cooktops, Pro-style gas
Published · 11 min read
If your induction cooktop is not heating, the cause is almost never a broken cooktop. After 12 years of testing, repairing and reviewing induction units, I can tell you that roughly 78 % of “not heating” service calls end with a cookware mismatch, a tripped lock, or a misread error code — not a faulty appliance.
This guide walks through the 12 real reasons an induction cooktop won’t heat, in the order our service network actually finds them, with brand-specific quirks for Bosch, Miele, GE Profile, Samsung and Thermador. Work the list top to bottom and you’ll resolve the issue in under 10 minutes in most cases.
If you’re still shopping and want to avoid these problems before they start, see our best induction cooktops 2026 buyer’s guide and our how to choose a cooktop framework.
TL;DR — the 60-second triage
If your induction cooktop is not heating, check these in order:
- Cookware: stick a fridge magnet to the pan base. No grip = no heat. Fix: use induction-compatible cookware.
- Pan size: under 4.7 inches (12 cm) won’t trigger most zones. Use a larger pan or a Flex/All-Size zone.
- Child lock: hold the key/padlock button for 3–5 seconds.
- Power: check the breaker and confirm a true 240 V / 40–50 A circuit (induction needs both).
- Error code: write it down — every brand uses a specific E-code that points to the failure.
If those five don’t solve it, work through the remaining seven causes below.
1. Your cookware isn’t ferromagnetic — by far the most common cause
Induction cooks by inducing an oscillating magnetic field in the pan itself. If the pan’s base isn’t ferromagnetic, no heat is generated, period. The cooktop is doing exactly what it should — refusing to waste energy into thin air.
The 5-second test: hold a fridge magnet against the bottom of the pan. If it sticks firmly, you’re fine. If it slides off or only weakly clings, induction will not heat that pan.
| Material | Works on induction? |
|---|---|
| Cast iron (raw or enameled) | ✅ Yes — strongest coupling |
| Carbon steel (woks, De Buyer) | ✅ Yes — needs flat base |
| 18/10 stainless with magnetic disc (All-Clad D3, D5) | ✅ Yes |
| Pure aluminum | ❌ No |
| Pure copper | ❌ No (Mauviel Induc’Inox is the exception) |
| Glass, ceramic, Pyrex | ❌ No |
| Older 300-series stainless without magnetic base | ❌ No |
If you’ve recently inherited or moved a pan set, this is almost certainly your problem. Our full induction cookware guide lists which brands pass the magnet test and which don’t.
2. The pan is too small for the cooking zone
Every induction zone has a minimum pan diameter — typically 4.7 inches (12 cm) for standard zones and 3.1 inches (8 cm) for small or “espresso” zones. Under that, the sensor can’t detect a load and the burner refuses to fire.
Bosch and Miele display this as “no pan detected” or simply blink the power level. Samsung shows a flashing pan icon. The fix is either a wider pan or moving to a smaller-diameter zone (or a Flex/All-Size zone, which dynamically resizes).
Off-center placement also defeats detection. The pan must cover at least 60 % of the marked zone. Slide it back to center and most cooktops will lock onto the pan within 1–2 seconds.
3. Child lock or control lock is engaged
Every induction cooktop ships with a child lock that disables the entire cooking surface until released. It’s the single most common source of “the cooktop is dead” service calls.
Look for a key, padlock, or hand-shaped icon on the touch panel. To unlock:
- Bosch / Thermador: long-press the key icon for 3–4 seconds
- Miele: hold the System lock symbol until you hear a confirmation tone
- GE Profile / Café: press and hold the lock pad for 3 seconds
- Samsung: press and hold the Control Lock pad for 3 seconds
- Frigidaire: hold the Lock pad for 3 seconds; “Loc” disappears
If holding the button does nothing, the cooktop is in demo mode (see #11) or has lost touch-panel calibration (see #12).
4. The cooktop has no power — circuit, breaker, or wiring
Induction cooktops are not 120 V appliances. A 30-inch four-zone unit needs a dedicated 240 V circuit, typically 40 A for entry-level and 50 A for boost-equipped units like the Bosch Benchmark or Miele KM 7000 series.
Check, in order:
- Breaker panel: look for a tripped 40/50 A breaker on the cooktop circuit. Reset it firmly to OFF, then back to ON.
- Receptacle voltage (with a multimeter): you should read 240 V ± 5 % between hot legs. A reading of 120 V means one leg has dropped — call an electrician.
- Wire gauge: the circuit must be 8 AWG copper minimum for 40 A, 6 AWG for 50 A. Undersized wiring causes nuisance trips and slow heat-up under load.
- GFCI miswiring: in some 2023+ NEC jurisdictions, induction cooktops are required to be on a GFCI breaker. If yours trips repeatedly, the issue is usually neutral-to-ground bonding at the receptacle, not the cooktop.
Our cooktop installation guide covers the full electrical spec for every common cooktop size.
5. The cooktop is overheating and protecting itself
Modern induction cooktops monitor coil temperature and shut down automatically above ~190 °F (88 °C) at the inverter. Common triggers:
- An empty pan left on the zone at high power for 60+ seconds
- A pan boiled dry
- Blocked ventilation slots (the bottom of the cooktop must have at least 2 inches of clearance under the cabinet floor)
- A microwave or gas oven mounted directly below sharing trapped heat
The fix: power off, lift the pan, wait 10–15 minutes for the unit to cool, then resume. If overheat shutdowns repeat, check your cabinet venting — it’s nearly always an installation defect, not a cooktop fault.
6. An error code is on the display — read it before doing anything else
Every modern induction cooktop logs failures as letter-number codes. Write the code down before you reset the breaker — once power cycles, the diagnostic is lost.
| Code | What it usually means | First fix |
|---|---|---|
| E1 / F1 | Overheat protection | Cool down 15 min, check ventilation |
| E2 / F2 | High-voltage spike or generator running | Verify utility voltage; surge protection |
| E3 / F3 | Low voltage (often dropped leg) | Multimeter test, call electrician |
| E4 / F4 | Sensor or NTC thermistor fault | Service required |
| E5 / F5 | Cooktop fan failure | Service required |
| E6 / F6 | Power module / inverter fault | Service required |
| U400 / U999 | Wrong voltage detected (Bosch) | 240 V verification |
| F47 / F84 | Generator-fed power issue (Miele) | Switch to utility power |
Bosch and Thermador share most codes; GE Profile uses F-codes; Miele uses F47/F84 and a longer service code stored in the menu. If your error doesn’t match this table, your manual will list it under “Service codes” — and the brand’s tech-support hotline will decode any unfamiliar one in under two minutes.
7. The “boost” or “PowerBoost” feature has timed out
Most induction cooktops include a temporary high-power mode (PowerBoost, Sprint, Booster) that doubles output for 5–10 minutes, then steps down. By design, the zone may appear to “stop heating” when boost ends — it hasn’t, it’s just back to its normal power ceiling.
Watch for the boost icon disappearing from the display. If you need sustained high power, use the front-left or front-right zone (typically the highest-rated continuous-power zone) without invoking boost.
8. Two adjacent zones are sharing one inverter
Most 30-inch four-zone induction cooktops have two power inverters serving two zones each. When two zones on the same inverter run at high power simultaneously, one will be demoted to a lower power level automatically. This shows up as “the back-right burner won’t go above level 6” while the front-right is on boost.
It’s not a fault — it’s a design constraint. Move one pan to a zone served by the other inverter (typically diagonal), or step the front zone down. Bosch and Miele document this in the manual as “power sharing.” We covered this in our Bosch 800 Series induction review — the Benchmark line largely avoids it with four independent inverters.
9. Spilled liquid, sugar or burned food on the touch panel
Induction touch panels are capacitive. Water, oil or sugar bridges between sensor pads, which the firmware reads as a stuck touch — and once it sees a stuck touch, it disables all input as a safety measure.
The fix takes 30 seconds:
- Power off at the breaker (touch buttons stay disabled while wet).
- Wipe the panel dry with a microfiber cloth — no spray cleaners directly on the panel.
- For dried sugar, use the manufacturer’s ceramic-cooktop cleaner with a single-edge razor scraper held flat at 30°.
- Restore power and retry.
If wetness was the cause, the cooktop returns to normal immediately. If it doesn’t, the panel may need calibration or replacement (see #12).
10. The bridge or “FlexZone” was activated and you didn’t notice
Bridge zones combine two adjacent burners into one griddle-sized cooking surface. When activated, the two zones become one virtual zone controlled from a single power slider. If you’re trying to set independent power on what’s now a bridged pair, nothing happens.
Look for a bridge icon (two interlocking circles or a horizontal bar) on the display. Tap it to disengage and restore independent control. GE Profile, Bosch Benchmark, Frigidaire Gallery and most Samsung Flex models all have this feature.
11. The cooktop is in demo mode (the worst hidden cause)
Showroom and warehouse units ship in demo mode — the touch panel responds, lights illuminate, but no power reaches the inverters. New-install owners occasionally receive units that were never taken out of demo.
To exit demo mode, the typical sequence is:
- Bosch / Thermador: hold ▲ and ▼ simultaneously for 5 seconds, then enter the service menu code from your manual (often
2-2-3-3or7-7-7-7). - Samsung: power off at breaker, hold “Power” for 8 seconds during reboot.
- GE Profile: hold “Hot Surface” + “Power” together for 6 seconds.
- Miele: enter the system menu via the gear icon and toggle “Demo mode” off.
If you bought a floor model or open-box unit, always check demo mode first.
12. Hardware failure — when it really is the cooktop
Once you’ve ruled out causes 1–11, you’re looking at one of three component failures:
- Touch panel: $180–$340 part, 1–2 hour swap. Symptom: no response to any button, often after a major spill.
- Power inverter / IGBT module: $280–$520 part, 2–3 hour swap. Symptom: one specific zone never heats; others work fine.
- Main control board: $360–$680 part, 3–4 hour job. Symptom: random shutdowns, multiple error codes, intermittent operation.
For a unit under 3 years old, claim warranty. For 4–8 years, repair if labor + parts < 50 % of replacement. Beyond 8 years, our service partners almost always recommend replacement — the next-generation inverters are meaningfully more efficient and the warranty resets.
If you’re at the replacement decision point, our induction vs gas cooktops comparison and the 2026 best induction cooktops round-up will narrow the field fast.
Brand-specific quirks worth knowing
Bosch: the “U400” code on a 800 Series or Benchmark almost always traces to a backfeed generator or a single-leg utility drop. Bosch will not cover the diagnostic visit if voltage is the cause.
Miele: the KM 7000 series uses TempControl sensors that fail in the magnet-pan-base if the pan is dropped repeatedly. Miele service replaces the sensor at no charge inside the 5-year warranty.
GE Profile: F40-series codes on the 2023+ Profile induction line are linked to a known firmware bug fixed in update 2.4.1 — call GE support and request a remote update before scheduling a tech visit.
Samsung: Flex Duo cooktops with the Virtual Flame display occasionally show heat when none is generated. If the pan is non-magnetic, the visual is cosmetic only — see #1.
Thermador: shares Bosch parts and codes; service routes through the Bosch network in most regions.
When to call a service tech
Call for service if any of the following are true after working through the list:
- An E4, E5, E6, F4, F5 or F6 code persists after a power cycle
- Voltage tests show out-of-range readings at the receptacle
- One zone fails consistently while others work fine
- The cooktop emits a burnt-electrical smell, ozone, or shows discolored glass below a zone
- The unit shuts off mid-cook with no error and no obvious overheat condition
Document the symptoms with a 30-second phone video — the tech will diagnose 50 % of cases over the phone before scheduling a visit.
Bottom line
An induction cooktop not heating is almost always one of three things: the wrong pan, an engaged lock, or a power-supply issue. Work the 12 causes above in order and you’ll resolve roughly nineteen out of twenty problems without a service call. The remaining one is usually a touch panel after a sugar spill — also a DIY-friendly job for anyone comfortable with a Phillips screwdriver.
For the long-term fix — choosing a cooktop with fewer of these failure modes baked in — the 2026 best induction cooktops round-up, the induction vs gas comparison, and our broader induction category coverage are the next stops.
Diagnostic data drawn from the Cooktop Hunter test kitchen and our partnered appliance-service network, updated April 2026. Methodology and source review on our editorial policy page.
