Microwave turns on but doesn’t heat food (all brands)
⚠️ This needs a qualified professional
This fault involves gas or mains electrical work. Don't attempt a DIY repair — UK law requires gas work to be carried out by a Gas Safe registered engineer. Below is what to check and describe to them, not step-by-step repair instructions.
When the turntable spins, the light comes on, and the timer counts down normally, but the food itself stays cold, the fault is isolated to the microwave’s actual heating components — this is one of the clearest “definitely needs an engineer” symptoms on this site, since there’s no safe external check that tells you anything more.
What’s safe to check yourself
- Confirm it’s genuinely not heating at all, rather than just heating unevenly or slowly — try a fresh cup of water on a full power setting for a minute or two and check if it’s warmed at all.
- Check you’re not accidentally on a “keep warm” or very low power setting rather than full power.
- Check the door is closing and latching fully — most microwaves have safety interlocks that will run the fan/light/turntable but deliberately disable the actual heating (magnetron) if the door isn’t detected as fully secure, as a safety feature rather than a fault.
⚠️ This needs a qualified engineer
If the door is closing properly and it’s genuinely not heating, the magnetron (the component that generates the microwave energy) or the high-voltage diode/capacitor supplying it has likely failed. Do not open the casing — microwaves store a genuinely dangerous electrical charge in an internal capacitor that can remain even when unplugged. This is one of the few appliance faults on this site with no DIY-safe checks at all beyond what’s listed above.