"Kristy Ogilvie" wrote in message
news
On Sat, 15 Dec 2018 21:13:28 -0000, Rod Speed
wrote:



"Mr Pounder Esquire" wrote in message
news
Kristy Ogilvie wrote:
On Sat, 15 Dec 2018 15:44:12 -0000, trader_4
wrote:
On Saturday, December 15, 2018 at 9:50:53 AM UTC-5, Kristy Ogilvie
wrote:
I'm in the process of fitting a Triton electric shower, and was
being nosy. I noticed it has a thermal cutout situated where the
water leaves the heater unit, this:
http://www.datasheet-pdf.info/entry/36TXE11 That cuts out at 105C
(ouch!) and it's also switching 20 amps when
it's rated at 10 amps, AND it only cuts off ONE of the two
elements. It does have another cutout on the other end of the heater
unit,
which cuts them both off. 1) Why have two cutouts?
2) Why overload the first one?
3) Why only cut off half the power?

I think I have part of your answer. If you pull up the actual
datasheet, it says this:

36Ts (automatic reset) are supplied to customer specified open and
close calibration set points with a tolerance on both set points.

Ah, I didn't read that far down.

It has a table showing the various versions and the temp ranges,
tolerance they can be *set* to. So, I think what you have is a part
that is
marked as the generic, ie 105C cut-off, but the cut-in and cut-off can
be
set by the manufacturer to the customer's reqts. What you have could
certainly be set to a lower cut-off temp.

That makes sense.

But having said that, the range of 71C
to 105C still sounds very high for a shower water heater. Any
chance you have the exact part number wrong? One letter or number
difference
matters.

Well presumably that's what it CAN be set to, and like you said, they
haven't.
If you have the current figured out correctly and it's really 20A,
then this part should not be in there.

An estimate, but I knew it was more than the 10A I thought the stat
was rated at. The shower is 8.5kW (35.5A at 240V), and I measured
the resistances of the elements (when cold) as 11.3 and 14.75 ohms,
with the stat switching the 11.3, which would be more than half the
full load, i.e. more than 17.75A. I see further down the datasheet
that the stat's actually rated 10A for 100,000 cycles and 16A for
30,000 cycles. Since it probably only kicks in if you overheat the
shower, 30,000 cycles is ok. Maybe it's wired up wrong and it should
be switching the smaller element? Or at 20A it can handle maybe
15,000 cycles?
As to having two cut-offs, that's very common. Typically there is a
thermostat for normal operation,

I don't think it's normal operation for the stat to operate - this is
a basic shower where the element should be on all the time (1 or both
depending on the user setting), the fine temperature control is by a
water pressure control. So I assume if you overheat it slightly,
then in warm mode the heater goes off, and in hot mode it cuts to
half power, then if it overheats further, the other stat cuts both
off.
then one or two thermal fuses that blow if it exceeds
normal operating range, eg it's being run with no water.

They're both stats as far as I can see, which auto-reset when it
cools back down. It would be damn annoying if you had to replace one
every time you overheated it.
If there are
two elements, it's also common in water heating applications for
there to be two thermostats to regulate the two elements, at least in
tank
type heaters.

**** off and die Hucker.

He can't **** off, his dick is too small to **** anything except cats.

On what do you base this absurd assumption?

We've got the video footage of you streaking with everyone pointing and
laughing.