Fixing a ceramic heater for a family member. Started blowing cold air.
It's very similar to this one:

https://en.wikipedia.org/wiki/File:G...mic_heater.jpg

It has a NC safety temperature switch fitted, this has failed open. One of
the spade lugs has clearly overheated. The switch is shown at the bottom
of this pic:

http://www.zuglet.com/ev/saturn/imag...micElement.jpg

It's marked KSD301 250V 10A. But there is no temperature marking

There is also a thermal fuse, this is OK.

This ebay auction:

http://www.ebay.co.uk/itm/262117559259

shows replacements with temperature values ranging from 40C to 160C. Can
anyone suggest what value I should choose?

The heater works OK with the wires to the switch shorted, but I would like
to replace it.

Thanks.

--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")

On 26/02/2016 15:07, Mike Tomlinson wrote:

Fixing a ceramic heater for a family member. Started blowing cold air.
It's very similar to this one:

https://en.wikipedia.org/wiki/File:G...mic_heater.jpg

It has a NC safety temperature switch fitted, this has failed open. One of
the spade lugs has clearly overheated. The switch is shown at the bottom
of this pic:

http://www.zuglet.com/ev/saturn/imag...micElement.jpg

It's marked KSD301 250V 10A. But there is no temperature marking

There is also a thermal fuse, this is OK.

This ebay auction:

http://www.ebay.co.uk/itm/262117559259

shows replacements with temperature values ranging from 40C to 160C. Can
anyone suggest what value I should choose?

The heater works OK with the wires to the switch shorted, but I would like
to replace it.

Thanks.


I've never known the bimetal dome to fail on these, always the contacts
or the little ceramic trigger out of position.
First with a soldering iron barrel , confirm by listening for a click
over, then repeat with a thermometer, glass or pyro.

En el artículo , N_Cook
escribió:

I've never known the bimetal dome to fail on these, always the contacts
or the little ceramic trigger out of position.
First with a soldering iron barrel , confirm by listening for a click
over, then repeat with a thermometer, glass or pyro.

It's open circuit, with a burnt spade terminal. Trust me, it's u/s.

--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")

On 26/02/2016 16:16, Mike Tomlinson wrote:
En el artículo , N_Cook
escribió:

I've never known the bimetal dome to fail on these, always the contacts
or the little ceramic trigger out of position.
First with a soldering iron barrel , confirm by listening for a click
over, then repeat with a thermometer, glass or pyro.

It's open circuit, with a burnt spade terminal. Trust me, it's u/s.


But not the dome, hack into it and extract the dome.
Now not constrained, you need to make sure it does not fly off , when
it flips to the opposite state.

On Fri, 26 Feb 2016 15:07:03 +0000, Mike Tomlinson
wrote:


Fixing a ceramic heater for a family member. Started blowing cold air.
It's very similar to this one:

https://en.wikipedia.org/wiki/File:G...mic_heater.jpg

It has a NC safety temperature switch fitted, this has failed open. One of
the spade lugs has clearly overheated. The switch is shown at the bottom
of this pic:

http://www.zuglet.com/ev/saturn/imag...micElement.jpg

It's marked KSD301 250V 10A. But there is no temperature marking

There is also a thermal fuse, this is OK.

This ebay auction:

http://www.ebay.co.uk/itm/262117559259

shows replacements with temperature values ranging from 40C to 160C. Can
anyone suggest what value I should choose?

The heater works OK with the wires to the switch shorted, but I would like
to replace it.

Thanks.

If the measurement isn't stamped on it, can you measure the
temperature in that area when the heater is working properly and just
add a bit?

Even if you underestimate the value a bit, they aren't that expensive
to go up a notch?

Cheers, T i m

In sci.electronics.repair Mike Tomlinson wrote:
https://en.wikipedia.org/wiki/File:G...mic_heater.jpg

I have a similar heater that I bought here in the US, branded Holmes,
made in China. It is rated at 1500 W, 120 V, 60 Hz. As a first cut,
their product support page

http://www.holmesproducts.com/servic...neral-faq.html

says the "overheat shutoff temperature" varies from 149 to 265 F, or
about 65 to 130 C. Note that this covers both ceramic and non-ceramic
heaters.

Taking mine apart, the ceramic core is about 3.25 x 3.5 x 0.5 inches,
or about 83 x 89 x 13 mm. If yours is very different than this, then it
may need a different temperature rating!

The safety switch is an "open frame" design, like the one seen in the
picture you linked -

http://www.zuglet.com/ev/saturn/imag...micElement.jpg

- and not an enclosed one like the KSD301 Ebay link you gave. When
installed, the bimetal with contacts is about 0.125" or 3 mm away
from the top edge of the ceramic core.

It is marked AUONE, AUT95P, and has VDE and USA-Canada UL component
marking ("backwards RU").

Google leads me to http://www.auone.com/showproduct13.asp?ProID=1849 .
The part I have looks like their "AUT-P" series (with the white plastic
tab), which lets me *guess* that the "95" in the part number means
95 C (or 203 F). Again, this is _just a guess_.

Please proceed with caution. The house you don't burn down may be
your own.

Matt Roberds