THermocouple Is reading hotter than it should

[Elmoclayman]

Hi all,  I have a 1987 Carol  Suzanne electric kiln that I have been babying to try and get through this school year.   I recently replaced the thermocouple and the temp is reading nearly twice as hot as it should.  I usually bisque to about 1800 and even when the temp readout said 2350, it wasn't even close to my bisque temp.  Any suggestions?

Thanks

[oldlady]

we have some kiln experts here but they would like to see photos of the kiln and thermocouples and anything else that might be printed on the label.   i have never heard of that brand name and wonder if anyone else has.   the more info you give, the better the answer.

[neilestrick]

Did you install the correct type of thermocouple? What type did you put in? What type was the old one? The controller has to be set for the correct type.

[Elmoclayman]

1 minute ago, oldlady said:

we have some kiln experts here but they would like to see photos of the kiln and thermocouples and anything else that might be printed on the label.   i have never heard of that brand name and wonder if anyone else has.   the more info you give, the better the answer.

The kiln brand went out of business about 10 years ago, which is why you probably haven't heard of it.  Its model number: CSE-BX-10, Serial Number:391, 50amp, 240v, 3 Phase

[Elmoclayman]

1 minute ago, neilestrick said:

Did you install the correct type of thermocouple? What type did you put in? What type was the old one? The controller has to be set for the correct type.

I installed the only one they had that looked remotely like the old one.  But it was very different.  Guessing that's the main problem here

[neilestrick]

15 minutes ago, Elmoclayman said:

I installed the only one they had that looked remotely like the old one.  But it was very different.  Guessing that's the main problem here

Did you buy one, or use one that was in the studio? Any packaging that indicates what type is is? Post a pic of it, and the old one if you still have it.

What model is the controller on the kiln? Kiln companies don't typically make their own, so you may be able to find a manual for it that shows a setting for thermocouple type.

[PeterH]

Any relevance, or are there too many non-standard cables about?

Thermocouple Cable Colour Chart
https://www.pyrosales.com.au/blog/thermocouple-information/thermocouple-cable-colour-chart/

...and
https://www.hgsind.com/videos/how-identify-thermocouple-wire-color
In this video we’ll be focusing on the ANSI wire color coding used by the United States and Canada.

 

Edited November 29, 2022 by PeterH

[Bill Kielb]

This may help along with Peters chart. You are likely checking between 3 types: K, Type R, and Type S so if those colors are present on the old thermocouple it would be great to note. A picture of the back inside of the control board likely reveals a jumper setting or terminal marking could give a clue. Pictures here likely very helpful

 

Edited November 29, 2022 by Bill Kielb

[Jeff Longtin]

Did you do a Google search on the kiln? It looks like it was manufactured by Ceramic Fiber Fabrication (CFF) which became Keithcompany.com.

It looks like they are an industrial kiln manufacturer out of California. (BIG kilns in other words.) Interesting website.  They might have some information?

[Hulk]

Looks like Keith is still in business; there's a phone number here:
Furnace Kiln Repairs | Keith Company

Comparing readings might be helpful, given you have access to a portable pyrometer, else compare your new pyrometer reading to a cone pack?

There's more separation at higher temperatures...

The wire colors appear to be a good first step.

[Elmoclayman]

22 hours ago, neilestrick said:

Did you install the correct type of thermocouple? What type did you put in? What type was the old one? The controller has to be set for the correct type.

I installed the only one they had that looked remotely like the old one.  But it was very different.  Guessing that's the main problem here

[Bill Kielb]

5 minutes ago, Elmoclayman said:

I installed the only one they had that looked remotely like the old one.  But it was very different.  Guessing that's the main problem here

Pictures of old, new, circuit board could help

[Elmoclayman]

Thanks for all the information!  So I put the old thermocouple in and it is reading much lower than the actual temperature.  I'm not sure of the the type  of the old thermocouple.  After firing, it was "orange" hot inside, but the temp reading was saying 756 degrees F.  Once it cools, I will get some pictures to see if I can recalibrate for the new Thermocouple.  

I did buy a new thermocouple:  Alpine Thermocouple Type K 11gx12

[PeterH]

22 hours ago, neilestrick said:

What model is the controller on the kiln? Kiln companies don't typically make their own, so you may be able to find a manual for it that shows a setting for thermocouple type.

Still a very good question.