On Sat, 08 May 2021 04:55:47 -0700, John Walliker wrote:

On Saturday, 8 May 2021 at 11:22:53 UTC+1, Max Demian wrote:
On 08/05/2021 04:04, Rod Speed wrote:
"Tim+" wrote in message
et...
Nick Odell wrote:

The best tip I know of to preserve long life in a cordless kettle
is always to make sure it is switched off before removing it from
the base. It's pretty common to find that the switch contacts are
plated to resist pitting from arcing but the base contacts are not
- with the inevitable consequences.
(Mode/)


Yeah but, Ive never had one fail due to arcing.

I never have any arcing. The on off button on the base of the kettle
eliminates any arcing.
Do you mean the one you push down to switch it on, or the one inside
the base that isolated the contacts when there is no kettle on the
base?

There's also arcing of the contacts between the two parts.

It's not clear which contacts break first.

The kettle switch contacts... every time. The interlock pin in the
kettle plug is designed to unlatch the switch before lifting the kettle
off its base breaks the centre pin contact.


--
Max Demian



Within an hour of reading this thread my Daewoo glass electric kettle
failed! The fault was in the neutral connection in the base which I
fixed by opening the base up and bending the spring. Opening the base
was tricky because the screws had special slots with three radial
grooves spaced 120 deg apart.
They really didn't want anyone to fix it.


You got that right! :- However, the base socket isn't the problem. It
rarely ever is - we're now on our fourth such 3KW 1.7l kettle as of
yesterday's Argos purchase to replace its almost identical Argos sourced
predecessor, also a Cookware model as was the one before that - the first
of these four kettles had been a virtually identical Tesco special.

Built in obsolescence is a seemingly guaranteed feature of all these
Chinese manufactured 1.7l plastic 3KW jug kettles ime. Quite obviously,
the nominated point of failure is _never_ _ever_ the heating element
itself simply to avoid the risk of a potentially more dramatic failure
mode (and possible bad press publicity) whilst there are many more points
of virtually guaranteed 'silent failure modes' to choose from, favourite
of which are those that offer the cheapest remedial costs in the event of
miscalculation over the planned 18 to 24 month service lifetime optimised
to avoid honouring a 12 month warranty whilst not cutting too much into
the sales of replacement kettles.

Usually what fails is the rather 'poor' (by design), typically wishbone
shaped, interior plastic lever which the external 'switch paddle' is push
fitted onto. The first kettle (that Tesco special I think) had one such
linkage that was obviously under-engineered to allow it to break,
predictably enough, right where you'd expect it to, at a stress
concentration point where it made a right angled deviation to clear an
internal obstruction (there were another one or two such right angled
deviations afaicr).

I managed to effect a reasonably strong repair by drilling 0.5mm holes
into the broken ends and pinning them with SS spring wire splints and
epoxy glue. It had seemed such an obscenity to junk a complete kettle for
the sake of a ha'penny's worth of plastic that I felt it worth making an
effort to mock the Chinese manufacturers' attempt at screwing the end
user no matter the cost to the environment.

The second kettle, the first of the Cookware series, simply developed a
slow leak and, since it was black and SWMBI was hankering after a white
kettle, I simply purchased a replacement rather than try to effect any
form of repair.

This last unit developed a very strange fault just a few days ago,
starting by it taking to binding onto its base when trying to lift it up.
At first, it seemed like a sticky liquid had contaminated the base and
socket but giving it and the kettle a thorough clean made no difference.

A day or two later, it had suddenly, and without any warning whatsoever,
decided to not latch the power unless you held the switch paddle down for
20 seconds or so before letting it flick off to reset it again back to
on, after which it would boil as normal (and even shut itself down after
boiling for the 10 to 20 seconds it takes for the anti-boil dry mechanism
shut off to kick in - not something I'd normally allow).

It was only after completely emptying it out to take a closer look at
the switch assembly and retensioning the bi-metal disk with horseshoe
shaped cut-out that pushes the external lever into the off position and
reassembling it that I noticed that the centre pin contact was slightly
off centre. I used a pair of long nose pliers to straighten it out which
immediately stopped it binding to the baseplate.

I returned it to the kitchen to successfully demonstrate to SWMBI my
repair work. However, the next day saw the fault symptoms make a full and
complete comeback. This time, I examined the centre pin contact and, you
guessed it, it was once more out of alignment. I straightened it out once
more, not only curing the binding issue but, mysteriously, the latching
failure issue... at least for the next two or three brew ups at which
point I could no longer Ignore the pressure from SWMBI to buy yet another
replacement kettle after only seeing two years of service from this one
which in every other respect had proved perfectly fitted to its task.

This time I decided, in view of the two years we had gotten out of a 15
quid kettle with only a 12 month manufacturer's warranty, to spend the
extra £2.59 on an extended 3 year warranty for its 15 quid replacement.
Fifteen quid for 24 months is effectively a monthly 'rental' of 62.5p
whilst the £17.68 spent in total this time round would equate to just
49.1p per month over the next 36 months.

One final note; what was mysterious about this failure was, in spite of
similar stress concentration points in the clear plastic whishbone styled
switch operating lever, there had not been any structural failure as
witnessed in the Tesco Kettle. It seems that rather than mould it into an
'organic' stress concentration free design, they'd simply over-engineered
it to get round the 'lego bricks' inspired design brief originated in the
earlier design of that Tesco special.

The bit of this plug and switch mechanism assembly I need to examine
remains hidden from view and whilst the heater element contacts with said
assembly are via narrow lucar type push on spade connectors, those push
on contacts are welded onto the heater element pins at an angle that
makes disconnection just a little problematical - undoing the three
screws holding this assembly to the base of the kettle isn't the problem
this time.

However, now that we have replaced it with a new one, I can afford to
have a go, even if it's merely to satisfy prurient curiosity over what
cunning new trick of obsolescence the Chinese have gone for this time
round.

--
Johnny B Good