[Clayart] forced air burners

Becky Holloway clayotter at gmail.com
Fri Jul 8 13:55:48 EDT 2016


I’m trying to get a feel for what is a “normal” experience when firing with
forced air burners.  Are they easy to use or difficult?  Do they stay lit
once the thermocouple is satisfied?  If you’ve used more than one brand, do
you have a favorite?   Why?  For the past 15 years I’ve been firing a
potters’ guild kiln that’s about an 18 cubic ft. arched downdraft with 4
Venturi  burners; one at each corner parallel to the floor using natural
gas.  Many happy firings with that kiln.


So, a potter moving out of state was selling a kiln in great condition and
I bought it from him.  It’s also an arched downdraft kiln about 23 cubic
feet, built almost entirely of insulated fire brick and fired with 2 forced
air burners using natural gas. The burners are at the back corners.  (I
believe they are Ward burners in the standard configuration.)  He fired it
about 45 times and I’ve fired it twice.  After digging through his log book
I’ve discovered he had chronic problems with the burners--from his first
firing to the last.  (Less than half of his firings seemed to have been
trouble free—no notes indicating he had to re-light one or both burners.)


The first time I fired it we had difficulty keeping the burners lit.  We
wound up replacing both thermocouples but couldn’t make adjustments to the
gas settings without them going out. Got to about 2000 degrees; the kiln
bearly moving up temp-wise; shut it off and went to bed.  My husband used
to work in the heating and air conditioning field and was convinced the
thermocouples were the problem.   On the advice of the BASO people, we
purchased and installed a longer thermocouple which put the sensor farther
back.  The second firing went pretty well—I consider it a successful one;
got to cone 10 in about 12 hours (a bit long but o.k.); the pots looked
good overall, and we thought our troubles were resolved.


Yesterday we couldn’t get the burners to stay lit.  We're calling BASO
again--maybe the valves need replacing--and will check our gas pressure but
after the last firing we're really puzzled.  Ward's website says most of
the time it's kiln design not the burners but what's normal for forced air
burners?  If the gas and air are right, shouldn't they at least stay lit?


Becky

Clay Otter Pottery, Alaska
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