Manual Kiln Sitter - Test Fire FAIL

[Kiel]

Hello all! 

So I'm trying to get an OOOOOLD craigslist manual kiln up and running. Seemed like a good plan to test fire it before risking any actual projects. It is a 30-40yr old AIM kiln, model #2927 (heh, I'm 30-40yrs old... what does that make me?!? haha!). 

I've tried twice, with the same results. I'm trying to fire to Cone 04, but it switches off before the cone bends and releases the sitter. I've placed vertical small cones (in mini diy holders) all around the kiln at different heights, and they don't seem to be bending at all. The first time, it looks like the timer switched it off but the second time I made sure the timer didn't run out! It seemed to run okay for 6hrs, but switched off somewhere between 6 & 8 hours. I double and triple checked that the timer and kiln-sitter mechanisms were both still "on," even though it had turned itself off. 

I've checked to make sure the kiln's circuit from the house wasn't tripped, coming from the house (its fine).  But I DID see that one coil seems to be out. Its a BIG kiln,  so that's like 1 of 6 coils. Would that cause the whole thing to shut off after 6hrs? Also, I'm still waiting for my peep-hole plugs to arrive, but I can't see how that would effect anything too drastically. Would it?

I do plan on fixing the broken coil, but I'm worried that I may have a bigger problem on my hands! Whaddya all think? 

HELP! Thanks in advance!

[Bill Kielb]

Yes if it’s a sitter kiln then having one element out will not turn it off......... but running out of time would be consistent with all elements not working. You never mentioned about turning on switches to ramp this up so that is bewildering as there ought to be several. The sitter  (save timer not expired) should power the kiln until it’s triggered. Sounds like you need to trouble shoot the sitter and all the elements at this point.

Oh, and likely the switches that allow you to turn this thing on low, medium, high as well. Still if the sitter, timer, and circuit did not trip this off, it still should be running. Sounds like Time to thoroughly check and see where the power stopped.

[GEP]

8 hours ago, Kiel said:

the timer and kiln-sitter mechanisms were both still "on," even though it had turned itself off. 

Do you mean the weight had not dropped and the cone in the setter had not started to bend, but the button still popped out?

[Sorcery]

Have you opened the panels?

I set a rule for myself recently to never attempt a plug and play without making sure there are no nickels In the box. Ask me why! Lol.

It does sound like a dangerous situation at this point.

Heat moves things, this movement can be disconnecting things. Those disconnected things can start fires.

Safety first second and third.

 

Sorce

[neilestrick]

The only way the kiln can shut off is if the power button popped out. Typically that is because the timer has reached zero or the weight has dropped. So if the power button popped out but the timer was not at zero and the weight had not dropped, then your sitter probably needs cleaning. The mechanism by which the button stays in is basically a spring, and over time it can get corroded or gummed up. Take the sitter out and clean it up. Also check that the timer dial is on correctly and reading correctly.

[Sorcery]

24 minutes ago, neilestrick said:

The only way the kiln can shut off is if the power button popped out.

Perhaps a healthy, fully intact kiln.

Just the heat reported at some outlet boxes is enough to change seating of internals.

Like wiggling a phone power cord to get it to work.

I'm stuck on we still don't know what "shut off" means. Could still be losing power incorrectly.

Sorce

[neilestrick]

1 hour ago, Sorcery said:

Perhaps a healthy, fully intact kiln.

Just the heat reported at some outlet boxes is enough to change seating of internals.

Like wiggling a phone power cord to get it to work.

I'm stuck on we still don't know what "shut off" means. Could still be losing power incorrectly.

Sorce

Here's my thinking: If it was a digital kiln that was shutting down early then that would be more likely. They have lots of little wires that could be loose and cause erroneous readings or flickering power and cause it to shut down prematurely. But with manual kilns the power is either flowing or it isn't, and for it to not be flowing to the whole kiln means there's a problem at the sitter or with the power supply. Since he said the breaker didn't flip that means it's probably at the sitter. Even if the plug was getting hot or wires were getting hot, the power would still flow, he'd just have trouble getting to temp. I've seen power buttons that won't stay put, and yes, they probably pop out because everything shifts as the kiln heats up. I was just going off the information we had so far, and I agree we need more info on exactly what 'shut off' means.

[Mariey3]

So my kiln is doing this too. It has two ways it will start to power down, one is the timer runs out and the kiln sitter isn’t bent or two the kiln sitter bends and shut it off. When it runs out of time it shuts off but my kiln sitter is still in perfectly straight position. So presumably it hasn’t fired to cone 6? I had a catastrophic kiln explosion where the timer jammed and it over fired, and since then it hasn’t been working right. If the kiln sitter isn’t tripped then is it safe to say it didn’t reach that cone and I should be looking at the elements next??

[oldlady]

welcome to the forum, Marley.     notice that the original post is from July 30, 2020 and that the discussion ended that day.   lots of people do not read the dates so do not feel alone in that.   lots of people do not give an update after getting good advice here from people who want to help so nobody knows what happened in this case.

my suggestion is to start your own question, with lots of information about exactly what you are experiencing.   neil estrick is a kiln expert and you can trust his answers to be accurate as long as the information is complete enough to judge what might be wrong.  there are lots of helpful folks here, some are experts in certain areas and then there is me, just an old lady who reads.

[neilestrick]

5 hours ago, Mariey3 said:

If the kiln sitter isn’t tripped then is it safe to say it didn’t reach that cone and I should be looking at the elements next??

I supposed some shards could have gotten into the sitter tube and are affecting if the sitter rod is able to move as it should. You might need to take it apart and clean it out.

The timer has nothing to do with how long a firing will actually take to get to temperature. When it gets to zero it will shut off the kiln regardless of how hot the kiln it. You need to figure out how long a firing will take for your kiln to get to the desired cone, then set the timer to approximately 1/2 hour longer. That means doing a firing with the timer set too long. Always use the same turn-up schedule with every firing. If your kiln was firing fine, but now suddenly the timer is shutting it off before the cone bends, then that's a good sign that the elements are showing wear and possibly due for replacement.

[Callie Beller Diesel]

@Mariey3 In addition to what Neil said, if you haven’t got large cones and you’re firing an analog kiln, you should head to Plainsman and get some. That’s the only real way to confirm whether or not a firing got to the cone you were aiming for. You’ll need a box for the cone you’re aiming for, one hotter and one cooler. The boxes last quite a long time, so while it seems like an investment up front, it’s good value. If you need a replacement tube and rod, they should also carry it. If the small cone from your catastrophic firing got firmly stuck to the 2 prongs that hold the cone in place or the rod, it’s worth replacing those in any case. Again, Plainsman should carry them, but if they don’t, Ceramics Canada in Calgary does.