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kiln controller scare

updated fri 16 jan 98

 

Frank Helme on tue 13 jan 98

I want to post a mistake I made so that hopefully no one else will have the
same problem. I have a very good external kiln controller which has one
thermocouple (TC)doing the controlling. I also happen to have two other
thermocouples just measuring top and bottom temperature. Late one night I
set the controller to start a biscuit (english spelling?) run at 2AM, then
went to bed. I had put my vent fan which is behind the kiln on a timer.
As I walked upstairs I had a feeling to go back and check the kiln. I
opened the lid and saw that I had inadvertedly moved the contoller
thermocouple back into the kiln wall. That really scared me since if I had
not gone back, the controller TC would not have properly sensed the
temperature and the controller would have put the elements on full power.
My kiln sitter would probably have eventually shut off power, but my
greenware would probably all have cracked. The kiln controller might also
have shut down earlier since the TC might not have indicated the programmed
rate of 150F/hr. I now have to figure out how to fix the controller TC so
that it does not move. Nuf said.

frank helme in upstate NY
fhelme@mindspring.com

DWoodin521 on wed 14 jan 98

Thermocouples are made to accept a fitting that can be screwed into a flange
on the kiln. In many cases a ceramic supplier may not have this type and
either you go to the kiln mfg or industrial suppliers. Omega has
thermocouples with fittings.

Marc Kiessling on thu 15 jan 98

Hi Frank:
A good lesson to learn. Thanks for sharing. I added an electronic
controller to and old manual kiln. This required drilling a hole for the
new thermocouple. I didn't like the thing being able to move about, so I
carefully bent the two thermocouple wires 90 degrees where they exit the
kiln, then attached the connector block to the kiln with some strapping.
Solid as a rock. Hope this helps.
Regards, Marc (Victoria, B.C., Canada)
ps. some thermocouple can be bought with a 90 degree bend

------------------------------------------------------------------------
At 07:41 AM 1/13/98 EST, you wrote:
>----------------------------Original message----------------------------
>I want to post a mistake I made so that hopefully no one else will have the
>same problem. I have a very good external kiln controller which has one
>thermocouple (TC)doing the controlling. I also happen to have two other
>thermocouples just measuring top and bottom temperature. Late one night I
>set the controller to start a biscuit (english spelling?) run at 2AM, then
>went to bed. I had put my vent fan which is behind the kiln on a timer.
>As I walked upstairs I had a feeling to go back and check the kiln. I
>opened the lid and saw that I had inadvertedly moved the contoller
>thermocouple back into the kiln wall. That really scared me since if I had
>not gone back, the controller TC would not have properly sensed the
>temperature and the controller would have put the elements on full power.
>My kiln sitter would probably have eventually shut off power, but my
>greenware would probably all have cracked. The kiln controller might also
>have shut down earlier since the TC might not have indicated the programmed
>rate of 150F/hr. I now have to figure out how to fix the controller TC so
>that it does not move. Nuf said.
>
>frank helme in upstate NY
>fhelme@mindspring.com
>
>