Ken Moore on thu 19 sep 96
Can anyone speculate on what would cause a gas kiln, with a safety
thermocouple, to shut down at about 2000 degrees on a calm, cool day? I
thought I ran out of gas, but the company came to fill them and said they're
still half full.
Julie Moore
Dirty Bird Pottery
Manassas, VA
kenmoore@pop.erols.com
.....still looking for a used pugmill....I'll pay shipping
Tom Gray on fri 20 sep 96
Ken Moore wrote:
>
> ----------------------------Original message----------------------------
> Can anyone speculate on what would cause a gas kiln, with a safety
> thermocouple, to shut down at about 2000 degrees on a calm, cool day? I
> thought I ran out of gas, but the company came to fill them and said they're
> still half full.
>
> Julie Moore
> Dirty Bird Pottery
> Manassas, VA
> kenmoore@pop.erols.com
> ....still looking for a used pugmill....I'll pay shipping
Julie-You may need new thermocouples. When they get worn out they are
unable to "read" the heat and will shut off automatically.
Tom Gray
Seagrove, NC
lrh on fri 20 sep 96
Julie, I've had the same problem and, replacing the thermacouple fixed
the problem... It's the probe that sits in the pilot flame and looks
like it has a wire running down to the burner control. After months of
use, it goes bad and replacement is inexpensive and easy. Go to
any good hardware store and take the old one in so you get
another just like it.
Loran
______________________________ Reply Separator _________________________________
Subject: gas kiln cuts out
Author: Ceramic Arts Discussion List at ccmgate
Date: 9/19/96 11:18 AM
----------------------------Original message----------------------------
Can anyone speculate on what would cause a gas kiln, with a safety
thermocouple, to shut down at about 2000 degrees on a calm, cool day? I
thought I ran out of gas, but the company came to fill them and said they're
still half full.
Julie Moore
Dirty Bird Pottery
Manassas, VA
kenmoore@pop.erols.com
.....still looking for a used pugmill....I'll pay shipping
Andrew S Lubow on fri 20 sep 96
Clogged Oriface?
On Thu, 19 Sep 1996 12:17:49 EDT Ken Moore
writes:
>----------------------------Original
>message----------------------------
>Can anyone speculate on what would cause a gas kiln, with a safety
>thermocouple, to shut down at about 2000 degrees on a calm, cool day?
>I
>thought I ran out of gas, but the company came to fill them and said
>they're
>still half full.
>
>Julie Moore
>Dirty Bird Pottery
>Manassas, VA
>kenmoore@pop.erols.com
>....still looking for a used pugmill....I'll pay shipping
>
Talbott on fri 20 sep 96
>----------------------------Original message----------------------------
>Can anyone speculate on what would cause a gas kiln, with a safety
>thermocouple, to shut down at about 2000 degrees on a calm, cool day? I
>thought I ran out of gas, but the company came to fill them and said they're
>still half full.
>
>Julie Moore
>Dirty Bird Pottery
>Manassas, VA
>kenmoore@pop.erols.com
>....still looking for a used pugmill....I'll pay shipping
Julie---Could be that your thermocouple went bad at the worst possible
time--I had a similar occurrence this summer and fortunately I had a new
thermocouple nearby which I was able to install in about 10 minutes--always
keep a extra themocouple nearby--secondly it could have been your solenoid
device that malfunctioned---but more than likely the themocouple was at
fault--Also if the end of the thermocouple gets all carbon(ed) up it can
malfunction.--Make sure that your safety device didn't get unplugged --and
that there is still power getting to it..Let me know when you determine the
problem I would like to know...Marshall
Marshall Talbott
Pottery By Celia
Route 114
P.O. Box 4116
Naples, Maine 04055-4116
(207)693-6100 voice and fax
clupus@ime.net
Vince Pitelka on fri 20 sep 96
>Can anyone speculate on what would cause a gas kiln, with a safety
>thermocouple, to shut down at about 2000 degrees on a calm, cool day?
>Julie Moore
Julie -
The most common cause of such a shut-down, assuming that the thermocouple is
O.K., is the pilot light being extinquished, causing the thermocouple to
cool and thus to cause the baso valve to shut. The pilot can be
extinguished by either too much air passing it (too much draft) or by too
much back pressure at the burner ports. Different burner/pilot setups are
more or less sensitive to such problems. What kind of system do you have?
We have several old Norman updrafts with ceramic venturi burners, and if the
back-pressure during reduction is too excessive it will back up in the
burner ports and starve out the pilots. When coming out of reduction if we
open the damper too quickly the rush of incoming air will blow out the
pilots. If your kiln is an updraft with venturi burners in the floor, and
if the damper is ever abruptly opened, it could blow out the pilots. On the
occasion you mention, iIf the kiln shut off during a period when the kiln
was stable, with no adjustments being made, it is most likely because of the
increased convection as the kiln heats up. It simply eventually got to a
point where the air movement past the pilot was enough to blow it out. The
solution is to keep the damper closed enough to prevent this from happening.
Of course, you want to keep the damper closed as far as possible without
causing more reduction than you want, because it will give more even
temperatures and lower firing costs. That is a generalization, and may vary
depending on whether you have a downdraft or updraft, whether you have
natural draft or forced draft, and whether your kiln tends to fire hot at
the top or bottom. Tell us more and we can do the same.
- Vince
Vince Pitelka - vpitelka@Dekalb.Net
Phone - home 615/597-5376, work 615/597-6801
Appalachian Center for Crafts, Smithville TN 37166
Elca Branman on sat 21 sep 96
Check your kiln gods...Elca
Arturo Devitalis on sun 22 sep 96
I haven't read the previoius posts so this is likely to be a repeatr:
The connection made between the valve and the butt end of the couple is
critical and can deteriorate over time..keep that little nut tight and check
it particularly if the valve/couple connection see heat. Also use only
Johnson Huskies thermocouples and position them to be well out of the
radiant heat emmitting from the burnier port. Also no sharp bends allowed
in the copper connecting wire particularly in the area close to the valve
connection. Hope this helps
--
Arturo DeVitalis
arto@uhura.cc.rochester.edu
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