Tjo62@AOL.COM on mon 24 dec 01
I just had this same problem last month. The orifice on the pilot burner had
become partly blocked from corrosion. This caused the flow of propane to be
slower and the pilot would go out and then the safety would turn the big
burner off. I used a dental tool to clean them out which helped a little.
But then I replaced them with new ones. Good luck. Tonya
EDGOULD on mon 24 dec 01
My pilot keeps blowing out at one of the 4 burner ports on my down draft
propane kiln; usually this occurs at high temperatures when in reduction.
Back pressure I presume is the problem. I cover that port and let the
pilot/thermocuple cool down. It takes quite a while to relight; its a new
thermocouple and this rarely happens in any of the 3 other burners. ANY
SUGGESTIONS?
Edouard Bastarache on mon 24 dec 01
Hello,
changing the thermocouple will be less expensive
than calling the propane technician.
Later,
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
----- Original Message -----
From: EDGOULD
To:
Sent: Monday, December 24, 2001 8:53 AM
Subject: thermocouple & pilot
> My pilot keeps blowing out at one of the 4 burner ports on my down draft
> propane kiln; usually this occurs at high temperatures when in reduction.
> Back pressure I presume is the problem. I cover that port and let the
> pilot/thermocuple cool down. It takes quite a while to relight; its a new
> thermocouple and this rarely happens in any of the 3 other burners. ANY
> SUGGESTIONS?
>
>
____________________________________________________________________________
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melpots@pclink.com.
Michael Wendt on mon 24 dec 01
To All:
Grainger sells a device that senses when the pilot light has gone out and
relights it with a spark before the main gas valve drops out.
Item : FENWAL automatic gas pilot relighter stock # 2E338 cost $40-50
US (list price is about $100)
Happy Holidays,
Michael Wendt wendtpot@lewiston.com
Wendt Pottery
2729 Clearwater Avenue
Lewiston, Idaho 83501
1-208-746-3724
wendtpottery.com
You wrote:
My pilot keeps blowing out at one of the 4 burner ports on my down draft
propane kiln; usually this occurs at high temperatures when in reduction.
Back pressure I presume is the problem. I cover that port and let the
pilot/thermocouple cool down. It takes quite a while to relight; its a new
thermocouple and this rarely happens in any of the 3 other burners. ANY
SUGGESTIONS?
vince pitelka on mon 24 dec 01
> My pilot keeps blowing out at one of the 4 burner ports on my down draft
> propane kiln; usually this occurs at high temperatures when in reduction.
> Back pressure I presume is the problem. I cover that port and let the
> pilot/thermocuple cool down. It takes quite a while to relight; its a new
> thermocouple and this rarely happens in any of the 3 other burners.
Ed -
When this happens during reduction, it is usually because the back pressure
changes the flame flow pattern so that the pilot flame is no longer
impacting on the thermocouple. It will probably just involve a little tweak
to change the position of the thermocouple slightly to make sure that it
stays in the flame. At the stage of firing when the problem occurs, have
you compared the pilot flame on the errant burner with the pilot flames on
the other three?
It also might mean that you are reducing excessively. There should not be
any need for much back pressure at the burner ports.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Ceramic Design Group on tue 25 dec 01
> Chris wrote:
> "Take your thermocuples off, throw them away and pretend they never
> existed."
Vince answered this one correctly, and I'll just add that this is precisely
the type of "mis-information" that gets perpetrated on the list and those
who are just coming up the through the pottery lottery so to speak take it
as gospel. Well, my friends, this is not gospel and never ever should be.
Its really not only mis-information but it is wrong information, bad
information, and really does quite a bit of dis-service in a mere 12 words.
Its irresponsible, to say the least.
While thermocouple driven Baso valves offer a good degree of flame
supervision, they need to be cared for. Rarely does the valve itself fail.
I've seen them in the worst possible conditions installed in the worse
possible ways, but they work when care for. Its just the thermocouple, and
is a SIMPLE parts replacement even for the more mechanically illiterate. Any
potter with a gas kiln that uses Baso valves and doesn't have a few
replacements on hand should know better. Yes, we have all used that
venerable "C" clamp.......enough said...
But there are also available Baso valves for larger diameter pipes. I used
these massive devices with simple Pyronics pilots for years. Yes the
thermocouples do fail, even on these big puppies. These larger thermocouples
are of an open manufacture and should be installed with the opening pointing
down so that if your kiln is outside, it doesn't collect water and then burn
out and fail. Remember, these things generate milivolts of power and need
some TLC. But many a kiln has been built and will continue to be built with
them and they will indeed monitor a burner successfully.
A better system, and yes,. even for the more financially encumbered potter
is a simple flame rectification system. We have a very simple and very
inexpensive one that uses a Honeywell gas valve and control module coupled
through a relays to a Syscon controller. Jim Cooper of Cooperworks Kiln
Company uses this system on all his kilns. We have a 50 cubic foot kiln of
his design and we are approaching 500 firings. The safety system works
flawlessly and I know Jim will sell just the safety system. We replaced the
stock pilots with some Pyronics pilots, added North American Combustion
limiting orfice valves to meter the gas for each burner and manual butterfly
valves to control the air. There are some very expensive flame supervision
systems that are way overkill for most potters. Simple works, and there is
no substitute for making sure your gas kilns fire safely. Our system
monitors the kiln overnight and has preformed flawlessly.
There is also another way if you have a forced air system consisting of one
large blower powering multiple burners. A manual reset safety valve wired
into the blower in a series will shut the gas off in the event of an
electrical failure and will need to be manually RESET after a power outage.
Let's not be cheap and irresponsible when it comes to observing correct
safety procedures and not just "throw out those thermocouples." When
properly maintained and adjusted, they can save your life, your loved ones,
and your studio from catastrophe.
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
info@ceramicdesigngroup.net
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, Fed Ex,
etc.)
"Custom design and manufacturing for the ceramic arts, giftware and pottery
industries. Molds, models, and tooling for slip casting, jiggering and
hydraulic pressing. Consultation on technical issues such as clay bodies
glazes, and kilns."
Chris . on tue 25 dec 01
\> My pilot keeps blowing out at one of the 4 burner ports on my down draft
>propane kiln; usually this occurs at high temperatures when in reduction.
>Back pressure I presume is the problem. I cover that port and let the
>pilot/thermocuple cool down. It takes quite a while to relight; its a new
>thermocouple and this rarely happens in any of the 3 other burners. ANY
>SUGGESTIONS?
Take your thermocuples off, throw them away and pretend they never existed.
Get your FREE download of MSN Explorer at http://explorer.msn.com.
Steve Mills on tue 25 dec 01
Try moving the burner and its t'couple out of the kiln an inch or so,
not much more; that should allow it to entrain just enough secondary air
to stem the back pressure and ease the problem.
Steve
Bath
UK
In message , EDGOULD writes
> My pilot keeps blowing out at one of the 4 burner ports on my down draft
>propane kiln; usually this occurs at high temperatures when in reduction=
>=2E
>Back pressure I presume is the problem. I cover that port and let the
>pilot/thermocuple cool down. It takes quite a while to relight; its a ne=
>w
>thermocouple and this rarely happens in any of the 3 other burners. ANY
>SUGGESTIONS?
--
Steve Mills
Bath
UK
vince pitelka on tue 25 dec 01
Chris wrote:
"Take your thermocuples off, throw them away and pretend they never
existed."
Not only is this very irresponsible, and very bad advice, but you offer no
suggestion as to how this is suppose to work. If you are suggesting that
the Baso valves be eliminated altogether, then you really should keep such
advice to youself. Someone could injure themselves or someone else and/or
damage their property because of your careless and flippant "advice."
Baso/thermocouple systems work extremely well, and are a very inexpensive
safety system. They sometimes take a little tinkering to get them working
properly, but if they are correctly mounted, adjusted, and maintained they
give very little trouble long term, and the thermocouples very rarely need
replacement. The only exception to this is on salt and soda kilns.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
vince pitelka on wed 26 dec 01
Chris wrote:
"Thermocuples are not designed for use in high fire kilns and to suggest
they are neccesary to operate a kiln safely is just wrong. The only time
they have any real safety value is during a preheating when the kiln is cold
and then all the burners would likely have to blow out for a kiln to fill
with gas. After the kiln has reached a sufficient temperture any gas
entering would imidiately ignite. All the thermocuple is good for at that
temp is frustration when it burns out in the middle of a firing. Before the
thermocuple were potters typicaly exploding kilns?"
On a regular basis we get people on Clayart who grandstand about things they
obviously know absolutely nothing about, and this is a good example of that.
To those of you with high fire gas kilns, PLEASE do not listen to the
opinions from this "Chris," because he obviously does not have a clue about
Baso-thermocouple safety systems on gas kilns. They work perfectly fine on
high fire gas kilns, except for salt and soda kilns. Anyone who wants to
use a thermocouple/baso valve safety system on a gas kiln can contact Marc
Ward at Ward Burner Systems (see any issue of CM) or contact me. I have had
plenty of experience with Baso valve safety systems, and I know that they
can be perfectly save and reliable on high fire gas kilns.
Properly set up, a thermocouple will last indefinitely on a high-fire gas
kiln.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Chris . on wed 26 dec 01
Thermocuples are not designed for use in high fire kilns and to suggest they are neccesary to operate a kiln safely is just wrong. The only time they have any real safety value is during a preheating when the kiln is cold and then all the burners would likely have to blow out for a kiln to fill with gas. After the kiln has reached a sufficient temperture any gas entering would imidiately ignite. All the thermocuple is good for at that temp is frustration when it burns out in the middle of a firing. Before the thermocuple were potters typicaly exploding kilns?
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Ceramic Design Group on wed 26 dec 01
on 12/25/01 10:34 PM, Chris . at clayfirer@HOTMAIL.COM wrote:
Thermocuples are not designed for use in high fire kilns and to suggest they
are neccesary to operate a kiln safely is just wrong.
Wrong for whom? While I certainly do not wish to turn this into a ClayArt
diatribe and argument
thousands of industrial producers of ceramic products have combustion
systems that monitor gas pressure/high and low, air pressure high and low,
flame supervision with high temnperature thermocouples or flame
rectification etc. You can operate a kiln very safely without any flame
supervision if you wish.
The only time they have any real safety value is during a preheating when
the kiln is cold and then all the burners would likely have to blow out for
a kiln to fill with gas.
What would happen if after reaching say, 300-500 degrees F and your kiln is
outside and in winter, a large gust of wind blows out the burners with no
safety system? This is far past pre-heating. I would rather have my safety
system then shut the gas off, and they re-light manually. I also want to
have a life and leave my kiln to do its thing while I sleep, go skiing, etc.
etc. Any electrical power grid system is prone to power outages. I would
sure feel better if my system were monitored for electrical failure.
After the kiln has reached a sufficient temperture any gas entering would
imidiately ignite.
That is true.
All the thermocuple is good for at that temp is frustration when it burns
out in the middle of a firing.
Then it is up to the potter and the kiln builder to install CORRECTLY RATED
THERMOCOUPLES, or better yet, a flame rectification system that monitors a
mill-amperage current in the flame.
Before the thermocuple were potters typicaly exploding kilns?
There are many cases and I am sure that some of these cases may have
happened to potters on the list.
None the less, its not worth arguing over, and I think that if you are
content with how your kiln fires with whatever combustion system and/or
controls you have, and it works for you, that's really all that matters. But
to recommend that potters throw out their thermocouples is still
bad advice, ill-advised and mis-information, especially on this list.
Respectfully
Jonathan
--
Jonathan Kaplan
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
infor@ceramicdesigngroup.net www.ceramicdesigngroup.net
(use PO BOX for all USPS correspondence)
Plant Location
1280 13th Street
Steamboat Springs CO 80487
(use PLANT LOCATION for all UPS, Common Carrier, and Courier deliveries)
Terrance Lazaroff on wed 26 dec 01
Thermocouples are there for a reason. Point final.
They ensure safe interuption of gas flow to the burners. This means that if
for any reason the gas supply is cut off the valves will close so that when
the supply is returned to the line there will be no unignited gas in the
building. Not just the kiln.
Think about it.
Terrance
Rare - Earth - Design on wed 26 dec 01
Chris,
NOT TRUE! I have seen a four burner kiln explode when one burner =
failed, hell, I even have had mini explosions when lighting my kiln and =
the match has gone out, by the time I get another one lit and put to the =
burner there has often (in the past) been a muffled booooom. You are =
correct in stating that when a kiln reaches a sufficient temperature any =
gas entering would immediately ignite, but from this observation you =
should therefore deduce that all kiln explosions happen before this =
temperature is reached and therefore thermocouples are neccesary to =
operate a kiln safely, they are not neccesary if you stay watching the =
burners.
The answer to the question you ask is Yes and even after the =
thermocouple Yes.
Regards,
Bob Hollis
----- Original Message -----=20
From: Chris .=20
To: CLAYART@LSV.CERAMICS.ORG=20
Sent: Wednesday, December 26, 2001 5:34 AM
Subject: Re: thermocouple & pilot
Thermocuples are not designed for use in high fire kilns and to =
suggest they are neccesary to operate a kiln safely is just wrong. The =
only time they have any real safety value is during a preheating when =
the kiln is cold and then all the burners would likely have to blow out =
for a kiln to fill with gas. After the kiln has reached a sufficient =
temperture any gas entering would imidiately ignite. All the =
thermocuple is good for at that temp is frustration when it burns out in =
the middle of a firing. Before the thermocuple were potters typicaly =
exploding kilns?
-------------------------------------------------------------------------=
-----
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=
_________________________________________________________________________=
_____ Send postings to clayart@lsv.ceramics.org You may look at the =
archives for the list or change your subscription settings from =
http://www.ceramics.org/clayart/ Moderator of the list is Mel Jacobson =
who may be reached at melpots@pclink.com.=20
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