Hey, it’s electric!
Today we have a crappy Chinese Tea Kettle to take apart and see what makes it not tick. This is an Ovente model #GK83R bought less than a year ago. It randomly refuses to heat and smells of molten plastic.
As expected, the product label does not even list UL/ETL or anything remotely resembling safety certification.
Let’s start with the base to make sure power actually gets in.
Taking kettle apart
then pry two clips under the handle’s plastic insert from the top:
And finally remove it:
Remove one more screw under the wires and the whole glass carafe can be maneuvred off the kettle:
Power switch looks reasonable:
And this is how they drive these fancy blue LEDs:
The base holds a light pipe with two blue LEDs in it:
Now on to the actual heating element that’s bonded to the glass:
Taking power receptacle off, reveals the thermal switch housing with even more melted plastic.
Seeing how the chance of finding replacement parts is fairly slim, we might as well proceed to destructive disassembly to learn how things used to work:
The two white actuators are depressed when installed. One by the base, another by a bimetallic sensing plate that changes geometry when heated:
And finally let’s take a look at the power switch and the boiling detection:
A plastic chamber directs steam to a bimetallic thermostat. Once it reaches trip temperature, the metal disk snaps and pushes switch reset pin in, shutting the kettle off.
It’s an “interesting” design. From safety point of view it is done reasonably well, with two series thermal switches and grounded frame. The LEDs are driven in series through a large resistor, though the way the are reverse biased on every other AC cycle is a bint cringe-worthy. Why not stick them in parallel and back to back so that one is always forward biased at any given time? As it is, they are most likely just getting away with it thanks to a large series resistance limiting reverse breakdown current. Plus it’s easier to wire- probably a non-trivial consideration for cheap volume build product.
This teardown started as a quest to find out why the kettle is not working. It appears the weak design of power inlet and thermal switches resulted in way more heat being seen by parts than expected, melting thinngs and disconnecting Line circuit. Not much is fixable here, so the kettle is getting dismantled and sorted into recyclable parts and e-waste. Oh well, now we know what to look for in a new one. And don’t forget those safety certs!