Arnold Howard on fri 21 jul 06
From: "Forest Butera"
And yes, the clicking
> continues right up until it completes or fails.
When a digital controller adds more heat to the kiln, it
sends a signal to a relay. The relay clicks on, and power
flows to the heating element. When the kiln has enough heat
to maintain the rate programmed into the controller, the
relay clicks off.
The clicking right up to the end of the firing indicates
that either 1) the controller is turning off the relay to
slow down the kiln or 2) the relay is failing to stay locked
in the "on" position.
Please list the program that displays on the controller when
you press Program Review.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Forest Butera on sun 23 jul 06
Ok, I'm in the middle of another test fire again and it looks like its
going to fail again. The program (which I double checked before beginning
the fire with the "review" feature) is 500 F per hour to 2199 - no holds,
no slow down. This was the program that the Paragon tech suggested I do. I
am doing it for a second time without the vent running to see if the vent
was having an effect as was suggested by another person on this list.
Here's how it has gone (which was about the same as it did with the vent
running):
1st hour 511 degrees
2nd hour 498
3rd hour 468
4th hour 139 degrees
its up to 1957 and it is clicking quite often. I'm watching and it clicked
at went to 1958, 1859, clicked and went down to 1958, 1957, clicked again
went back up to 1958. This is what happens shortly before it gets FtL.
This is the second controller. This one acted more normal at lower
temperatures than the first one did. That one fired way faster than was
programmed.
Forest
Forest Butera on sun 23 jul 06
Howard, I had another question. You said it was normal for the lid
to "float" toward the end of the firing. Why is that? It seems that would
let in a lot of air so that with a vent it could be cooling down too much.
But I'm doing the current firing with the vent off which isn't helping the
temperature to climb. The lid is definitely floating - there's about an
1/8" gap all the way around. What's the purpose of that? Thanks.
William & Susan Schran User on mon 24 jul 06
On 7/23/06 7:39 PM, "Forest Butera" wrote:
> The lid is definitely floating - there's about an
> 1/8" gap all the way around. What's the purpose of that?
I'm sure Arnold will chime in here with the correct technical reason, but my
understanding is that the lid actually deflects/warps as it gets hotter. It
becomes concave (if I can remember my concave/convex directions). The edges
raise up and the middle is bowed down slightly, forming a gap around where
the lid and top of wall meet. The bricks are also expanding, so the lid has
to float/move to prevent cracking.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
William & Susan Schran User on mon 24 jul 06
On 7/23/06 7:33 PM, "Forest Butera" wrote:
> The program (which I double checked before beginning
> the fire with the "review" feature) is 500 F per hour to 2199 - no holds,
> no slow down.
We have two L&L's with Barlett controllers at school.
We set the ramp speed to 500=B0F per hour for our crystalline firings.
We want to go up very fast.
At home with a manual kiln, I get to ^6 in 4 hours.
The fasted we've gotten the programmable controlled kilns to get to ^6 is 6
hours.
On some firings, with ramp speed set to 500=B0F climb, heavier loads/more kil=
n
furniture, especially towards the end of the firing, we'll get an "ERR"
message, program shutting down.
If the controller is reading the thermocouple and the kiln is not rising at
500=B0 per hour for a certain period of time, then the controller figures
something is wrong and shuts the kiln off.
I'd suggest trying a slower heat rise setting - 250/300=B0F per hour.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
Arnold Howard on tue 25 jul 06
From: "Forest Butera"
> Howard, I had another question. You said it was normal for
> the lid
> to "float" toward the end of the firing. Why is that? It
> seems that would
> let in a lot of air so that with a vent it could be
> cooling down too much.
> But I'm doing the current firing with the vent off which
> isn't helping the
> temperature to climb. The lid is definitely floating -
> there's about an
> 1/8" gap all the way around. What's the purpose of that?
> Thanks.
The kiln becomes taller as it reaches high temperatures.
This is because the firebricks expand when they get hot.
However, the lid should not lift up at the front. If it
does, it is because the lid isn't "floating." The hinge rod
passes through oval holes so that as the kiln becomes
taller, the lid doesn't bind. If it binds, it will lift up
at the front.
As Bill explained, the inner lid surface expands more than
the outer cooler surface. Therefore, it bows inward slightly
toward the firing chamber. This is normal. For this reason
you will see a thin line of light around the lid, since the
lid is no longer a flat surface resting on the flat firing
chamber sidewalls. Surprisingly, there is very little heat
loss from around the edge of the lid--unless the lid rises
in the front, which it should not do.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
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