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Help with using a Duncan Automatic Teacher-Plus Kiln


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They're quite heavy so they don't move around a lot. I put mine on the back seat of a convertible mini and drove about 300 miles from the borders of Scotland to the islands and it never moved. If it can take those roads, it can take anything :D

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  • 4 months later...

Hi all, and thank you for all the great information. I am also new at this and just started firing a Duncan Teacher Plus EA-820. It has only one knob and no toggle switch. I fired it for the first time yesterday. I started at the 10:00 position for 1:15 then moved to the 8:00 position. I checked on it after an hour or so and it was fine, then the next time I checked on it it had shut off.  I had an 06 cone in the cone sitter, the top peephole was open. There were just a few small pieces of work in there, essentially empty. Total run time: Less than 3 hours.

This morning I opened the kiln and turned the dial to 12:00 (off). There was low consistent buzzing. Then I turned it counter clockwise to the next "stop" on the dial, about 11:00. I could hear bottom only heating elements cycling on and off. So I timed the cycles at various positions and figured I would share the data. Time is in seconds (s). Times are approximate as I am not perfect with a stopwatch. 

Dial Setting On (s) Off (s)  
12:00 Constant but low    
11:00 7 17
Only lower elements
10:00 7 16
9:00 8 14
7:30 8 11
6:00 11 9
5:00 16 7
4:00  Upper elements kick in, each cycle separately

 

So today I fired the kiln and left it on the "off" position for about 2.5 hours. The kiln was red hot. I turned it to the 11:00 position and after about 90 minutes it had shut off.  The kiln ran almost 4 hours total. Do you think the kiln being empty has a huge bearing on this? I am afraid to fire my work until I have the kinks worked out.  Is it a thing to open the lid a bit to keep the temp from getting too hot too fast? I was initially thinking the "off" position (12:00) was a candling setting but who knows?! Any thoughts out there? I appreciate you!

 

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3 hours ago, StephSlone said:

Any thoughts out there?

I think this is the right manual
Duncan Energy-Saver ES & EA Instruction Manual LX851
https://eadn-wc04-7751283.nxedge.io/wp-content/uploads/LX851_Duncan_Energy_Saver_Owner_Manual.pdf

On p13 it says

image.png.bd92ad689eb2957c147a889ab1544e87.png

What is the relationship between your "clock-face" numbers and any labels on the on the kiln, such as
image.png.996f6df34a41693e6d9e3a93b5580dc3.png

... and why doesn't this picture show anything that obviously corresponds to the "low" marking mentioned in the manual?

Unless "off" in the picture is the equivalent of "low" in the manual? Which makes some operational sense (as you report that it does heat up the kiln) but no linguistic sense.

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lots of questions about this particular kiln.   the word automatic has a totally different meaning today.  back then it meant "this kiln has an automatic shut off device called a kiln sitter, like a baby sitter.   you do not have to watch the heat color any more to know when to turn it off, it turns off by itself automatically."

just follow any kiln manual, they are basically the same.

Edited by oldlady
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This makes me think your dial is a little off set. Is there a position between "Off" and 11 o'clock where it is actually off? (No buzzing or clicking or heating.)

Kiln controllers only shut the elements on or off, they can't turn the current down. Low settings have more off time and less on time, as you have measured above. This makes me think your dial is working, it is just twisted a bit compared to the markings.

4 hour firing is mighty fast but could work. Most of my stuff would blow up if it was green ware and didn't candle it for half a day first. You should be able to control it better than this, and not by opening the lid!

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Thank you for your input. That’s so interesting what you said about the elements only being  either on or off, not low. There is no point on the dial that I could find where the elements didn’t heat up. In the “off” position the elements don’t buzz nearly as loudly  as they do at 11:00 and It is only the lower elements that heat up at the lower settings.  The upper elements don’t kick in until the “hi fire” setting. 
I think I will work on trying to find a lower setting between 12 and 11. It’s got to be there! Thank you so much for your help!!!!

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13 hours ago, StephSlone said:

It could be stuck! Do you know how one would remedy that?! 

Unfortunately this is a fairly complex kiln. An early attempt to automate before digital controls. It did have some popularity though given how many seem to still be kicking. To solve this you likely will need solid troubleshooting skills. Some of your symptoms cause and effect are described throughout the thread. The two special timers used in this design (bottom of schematic) tend to go bad after awhile and are not readily economically replaceable. That it does not shut off when switched to off may indicate the infinite switch does not function, especially if the pilot light does not turn off. My best thought: if testing relays is not in your wheelhouse then maybe If you can find a good kiln tech, this is one that may be worth every penny to have it diagnosed. In fact the tech may suggest removing much of the complexity of this thing and installing two simple infinite switches in place of the relays and timers.

Edited by Bill Kielb
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  • 4 weeks later...
On 1/19/2023 at 12:14 PM, Bill Kielb said:

@Dom_Llam
Here is a generic explanation from an old Duncan wiring supplement that I believe was mislabeled on their website. I believe it is applicable to all models with the switch and timers.

This may help

6F5D1C9B-CC05-45DD-BD50-FC00D84B9D85.jpeg

@Bill Kielb That was incredibly helpful, thank you so much!

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  • 1 month later...

In the off-chance that any needs to replace the infinite switch - I just replaced mine with this and it works a treat. Very easy to fit, just take out one plug at a time and match it up to the new one. 

 

https://www.ebay.co.uk/itm/141185298305?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4uGYTVfwQOK&sssrc=2349624&ssuid=iC-XyCNQT4W&var=&widget_ver=artemis&media=COPY

 

And very cheap, cost me £8. 

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  • 4 months later...

Hi there, I have this same kiln and it does fire really fast, usually stops somewhere between 5.5 to 6 hours whether it's a ^04 Bisque or ^5, ^6 Glaze fire.  @JohnS did you find a firing schedule that kept it on for longer that 6hours?  

Im a hobby potter, making mostly bowls, mugs and tumblers. I've done 27 firings in this and most things have turned out great, even tho its a fast fire. Since it was so fast tho, I bought a pyrometer so I could see what was happening.   Prior to having the pyrometer, I found that even if I did the slow method (moving dials around the clock as mentioned in this thread) it still shut off in under 6 hours. ( that's why I bought the pyrometer) Even tho it fired fast, the Kiln sitter cone was a perfect bend and all the witness cones performed as expected.  So this makes me wonder...maybe it's just a fast firing kiln?  And if so, is that a bad thing? Like others on here, I went in search for answers from the experts and am thankful for all the guidance.  

I'm doing a ^5 glaze fire right now.  I started it, at 10:45, with the dial on Hi-Fire and the temps/times are as follows: 

12:48 @ 631 Celsius 

2:07 @ 968 Celsius 

2:44 @ 1075 Celsius 

3:15 @ 11:45 Celsius 

3:30 @ 1162 Celsius 

3:45 @ 1174 Celsius 

3:50 @ 1177 Celsius 

3:55 @ 1179 Celsius 

4:00 @ 1180 Celsius 

4:05 @ 1182 Celsius 

4:20 @ 1183 Celsius 

4:26 @ 1183 Celsius  and the sitter dropped, it turned off.  Start time 10:45a, off at 4:26p.

I have no idea if those times/temps are good or bad.  Hoping someone on here can advise-- is the increase in temp proper for the amount of time? 

When I open it tomorrow, I will check all the witness cones, I place them on each shelf, but typically they all perform as expected. 

 

 

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Hey, 

Aye, so, it does seem like a fast firing kiln, for me I've found this not to be a problem certainly with the clay and glazes I've been using. Cones bend properly meaning that it's reaching it's temperature and for the correct duration, I'm sure that for some folk using certain glazes then the results might not be quite what they're looking for, but if you're happy with how your work is turning out Amd the colours your getting then it's a win! 

 

What I tend to do these days is turn the dial to 11 o'clock and leave for and hour and the peephole open, then put them back in and turn to 10 o'clock for another hour, then dial it up to ceramic for a bisque fire. I think I got an 11 hour fire last time doing that.  

 

For cone 6, I repeated the initial step but kept ramping up an hour at a time for the first 4 hours then whacking it up to hi-fire, last firing I got 9 hours for a glaze I think. 

Then it was a case of letting it cool down properly before opening and everything had fired properly/food safe. 

 

It seems to be a decent cheap kiln so long as the switches and elements work and you don't mind dialling it up manually for the first few hours. 

 

Good luck! 

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  • 4 months later...

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