Dale Cochoy on mon 20 may 02
----- Original Message -----
From: "Arnold Howard"
Subject: Re: Kiln firing problem
> The way I understand this message, the kiln under-fired by several
> cones, yet the controller showed the correct temperature when it
> shut off.
> You might also replace the thermocouple and fire again. I recommend
> keeping a spare thermocouple on hand.
>
> Arnold Howard
> Paragon Industries, Inc.
Exactly.
I removed the thermocouple today and inspected it. Before doing so it
appeared to read the room temperature of the kilm pretty close as I
figured it, and, it went up slightly as I enclosed it in my fingertips. But
it was pretty crusty with black carbon "soot". So, I removed it and brushed
the tack weld with a small brass brush to clean it off. Sure enough, when
cleaned off I could see a crack ( actually a couple tiny ones and one larger
one) across the surface of the junction weld. Hmmmm. I recalled the
manufacturer and tallked to technical help. We convinced me ( :>) ) that
that might be the problem as the kiln gets hotter the thermocouple junction
seperates and is causing a faulty operation of the digicontroller. Anyway,
I ordered another thermocouple for a try, and a spare for the next time this
happens when I need to get something done on time and have a questionable
thermocouple. After a refire check I'll let everyone know if that was indeed
the problem that was causing the firing to be a couple cones low even
though the controller said it was the correct temp. Also, I'll be sure to
use a cone pack in peep hole during this firing so I can be sure. BTW, I
don't have a pyrometer yet but that's now soon to be purchased. I sure wish
I'd had that little item beforehand.
Regards,
Dale
Earl Brunner on mon 20 may 02
Yeah, well, it sounds great in theory. At the art center where I fire the
kilns,
they pay me $20.00 per hour for my time. They won't do it for the length of
a
firing. I fire at least 4 firings a week, about half bisque and the other
half to
cone 6 using Ron and Johns's firing schedule on the controller. They get
what they
get. Cones are not even put in every firing. just occasionally for spot
checking.
william schran wrote:
> I have advised folks in the past to use witness cones (that can be
> viewed through spy hole) for every firing, whether bisque or glaze.
> This continues to be the only way to really see what the work heat is
> doing. Anybody that relies on a controller or Kiln Sitter to shut of
> the kiln is simply asking for problems.
>
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Dale Cochoy on mon 20 may 02
I was wondering if anyone could shed a little light on a firing problem
before I fly into sending components to the manufacturer.
I have a "Perfect Fire" kiln that I've only had two problems with over the
past three years. Model PF2329 #5-32-94, digicontrol DTP-56DCE. A
thermocouple went out ( which does display an error code and locks out
firing) and during some power outages here the digicontrol got out of
calibration and I easily got that back after David Coggins sent me the
digital controller calibration procedure.
A week or so ago I bisque fired a load ( to cone 04) and it looked ok.
Now, I only use the digi controller since it works great and I don't view
cones , especially for bisque., but, it appeared ok.
I glazed and high fired w/ digital control and "soft" firing which I've
found best for me. Now, I don't view cones but do set cone 5&6&7 inside to
double check when it's all done. Unit setup, ran ok as per usual. No
unatural things seen. I wasn't near it when it shut off however and it was
storming badly. After cooling I opened up and the pieces/glaze didn't look
any different than bisque ( although controller was running normally
apparently for 14 hours) . I thought, MAYBE, power dropped out for a few
seconds near end of firing and it stopped. ( our power drops out for a few
seconds here ALL THE TIME, a real pain!).
Cones were white now but unbent any. So, I did cal of digital controller to
be certain it was ok, no problem. Setup ok, and refired. Same times,
settings, etc. This time I was sure I was at kiln at 3AM to actually watch
it slow down towards end for soft-fire and shut off. Looked great. Temp
readings looked normal and shutoff temp reading normal.
Opened up next eve and same results.
I called Manufacturer and they said to send controller in and thermocouple.
( I never did get any error codes for thermocouple, elements, etc). I
thought possibly an element problem but they said that would usually cause
an over-fire condition. and, like I said, no error codes!
Soooooo, any ideas ( other than the expected warnings to use viewed cones
now while firing!). This unit has performed flawless for several years doing
it just the way I have operated it.
I had to immediately leave for out of town for 4 days so I'm sending this
before unloading and tinkering to possibly save me some time. David Coggins
couldn't help again as he was leaving immediately for US trip.
Regards and thanks in advance,
Dale Cochoy, Wild Things Bonsai Studio, Hartville, Ohio
DaleCochoy@Prodigy.Net http://www.WildThingsBonsai.Com
william schran on mon 20 may 02
Dale wrote: "I only use the digi controller since it works great and
I don't view
cones , especially for bisque., but, it appeared ok."
He also wrote that he uses cones in the glaze firing, but only to
check the firing after cooling.
I have advised folks in the past to use witness cones (that can be
viewed through spy hole) for every firing, whether bisque or glaze.
This continues to be the only way to really see what the work heat is
doing. Anybody that relies on a controller or Kiln Sitter to shut of
the kiln is simply asking for problems.
I use pyrometers to check rate of heat climb and rate of cooling. I
also use Kiln Sitters as a back up, just in case, but not normally to
shut off the kiln. Witness cones are used in every kiln I fire.
It's as simple as that.
Wait, I take that back. For raku I use nothing but my eyes to judge
glaze melt to my satisfaction.
Bill
Arnold Howard on mon 20 may 02
The way I understand this message, the kiln under-fired by several
cones, yet the controller showed the correct temperature when it
shut off.
I believe the problem is either the controller or the thermocouple,
and not the kiln. Several ideas:
Move the thermocouple tip back and forth. If the temperature
becomes erratic, replace the thermocouple.
Are the thermocouple connections tight?
You might also replace the thermocouple and fire again. I recommend
keeping a spare thermocouple on hand.
Arnold Howard
Paragon Industries, Inc.
--- Dale Cochoy wrote:
> I was wondering if anyone could shed a little light on a firing
> problem
> before I fly into sending components to the manufacturer.
> I have a "Perfect Fire" kiln that I've only had two problems with
> over the
> past three years. Model PF2329 #5-32-94, digicontrol DTP-56DCE.
> A
> thermocouple went out ( which does display an error code and
> locks out
> firing) and during some power outages here the digicontrol got
> out of
> calibration and I easily got that back after David Coggins sent
> me the
> digital controller calibration procedure.
>
> A week or so ago I bisque fired a load ( to cone 04) and it
> looked ok.
> Now, I only use the digi controller since it works great and I
> don't view
> cones , especially for bisque., but, it appeared ok.
> I glazed and high fired w/ digital control and "soft" firing
> which I've
> found best for me. Now, I don't view cones but do set cone 5&6&7
> inside to
> double check when it's all done. Unit setup, ran ok as per
> usual. No
> unatural things seen. I wasn't near it when it shut off however
> and it was
> storming badly. After cooling I opened up and the pieces/glaze
> didn't look
> any different than bisque ( although controller was running
> normally
> apparently for 14 hours) . I thought, MAYBE, power dropped out
> for a few
> seconds near end of firing and it stopped. ( our power drops out
> for a few
> seconds here ALL THE TIME, a real pain!).
> Cones were white now but unbent any. So, I did cal of digital
> controller to
> be certain it was ok, no problem. Setup ok, and refired. Same
> times,
> settings, etc. This time I was sure I was at kiln at 3AM to
> actually watch
> it slow down towards end for soft-fire and shut off. Looked
> great. Temp
> readings looked normal and shutoff temp reading normal.
> Opened up next eve and same results.
> I called Manufacturer and they said to send controller in and
> thermocouple.
> ( I never did get any error codes for thermocouple, elements,
> etc). I
> thought possibly an element problem but they said that would
> usually cause
> an over-fire condition. and, like I said, no error codes!
>
> Soooooo, any ideas ( other than the expected warnings to use
> viewed cones
> now while firing!). This unit has performed flawless for several
> years doing
> it just the way I have operated it.
> I had to immediately leave for out of town for 4 days so I'm
> sending this
> before unloading and tinkering to possibly save me some time.
> David Coggins
> couldn't help again as he was leaving immediately for US trip.
> Regards and thanks in advance,
> Dale Cochoy, Wild Things Bonsai Studio, Hartville, Ohio
> DaleCochoy@Prodigy.Net http://www.WildThingsBonsai.Com
>
>
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