An lg microwave not heating lights up, the turntable spins, and the timer counts down — but the food stays cold. Because the parts that produce heat carry lethal high voltage, this is one fault that is mostly a service item.
LG microwaves produce heat with a magnetron and (on NeoChef models) a Smart Inverter, both high-voltage components, so while many faults post an F-code, the heat-producing parts are strictly a technician’s domain. We start with the everyday causes you can check yourself, then explain the signs that point to a part that genuinely needs a hands-on repair.
What a lg microwave not heating usually means
Microwave heat comes from the magnetron, fed through a high-voltage diode and capacitor (or an inverter on NeoChef models). A failure in any of these stops heating while everything else still runs. These components store a dangerous charge even unplugged, so internal work is for a technician.
First checks you can do
Start with the checks you can safely do yourself. Each one rules out a common, inexpensive cause, and together they resolve the majority of cases without a service visit:
- Power-cycle the microwave by unplugging it for a minute to clear a stuck-key F10/E10.
- Confirm you are not in a defrost or low-power setting that heats weakly.
- Make sure the door closes fully — a door switch issue can stop heating.
- Test with a cup of water for one minute to confirm the no-heat symptom.
Take these in order and test whether the problem has cleared before moving to the next. If you do end up needing help, having worked through them gives the technician a useful head start.
Reading the LG display for a lg microwave not heating
Note any code before you act, because it narrows the diagnosis more than any other clue. A good first move for most LG codes is a power-cycle: unplug for one to five minutes, or trip the breaker for 30 to 60 seconds, then restore power. If the code returns straight away, treat it as a real fault pointing at the named part.
- F10 / E10 — stuck key (often fixed by unplugging for a minute).
- F1 — mainboard · F2 — thermistor/temperature.
- F11 — inverter comms · F13 / F14 / F15 — inverter over-current/voltage.
Note the exact characters, including whether letters are upper or lower case, since LG sometimes uses capitalisation to separate a real fault from a normal status message.
When it is a fault, not a habit
If the everyday checks above do not resolve it, the problem has likely moved from something you can adjust to a component that needs testing or replacing. These are the signs that point that way:
- The microwave runs but never heats — a failed magnetron, diode, or inverter is the likely cause.
- A humming or buzzing with no heat can point to the high-voltage circuit.
- These repairs require discharging the capacitor and are not a DIY job.
At this point a proper diagnosis beats guesswork, since the remaining causes involve a specific part or electrical testing. A technician can meter the suspect component and fit a genuine LG part so the repair lasts.
Putting it together
Work the checks above in the order given. Most LG microwave faults of this kind clear at one of the early, owner-checkable steps; the ones that do not point to a specific part and are worth a proper diagnosis rather than guesswork. Move from the simplest cause outward, confirm each step before the next, and treat a returning code or a lingering symptom as your cue to bring in help. A little routine care afterwards prevents most repeat calls, since LG builds these microwaves to last.
Related reading: LG microwave error code archive, LG microwave sparking, and our microwave repair service.
Book LG microwave service
If these steps do not resolve it, our experienced technicians repair LG microwaves with genuine parts and a labour guarantee. Schedule a visit, see what our microwave repair service covers, or confirm your model details on the manufacturer’s site at lg.com/us.
