Kiln gas type question
Posted 30 October 2012 - 04:33 PM
I have an Updraft kiln that I purchased used. It was actually refurbished at SPS and thenbought by someone whom I purchased it from.
The kiln was setup to run propane when I bought it asreported by the previous owner, but he admitted that he never lit thekiln. I purchased it and went and boughta 100lb tank and some hoses to hook it all up. I have fired the kiln twice, but the main valve on the burners does not seemto be setup for high pressure Propane, but rather lower pressure naturalgas. I say this because it is barelyopen like 5% open in order to run the burners at the right level. And when I try to open the main value all theway and adjust the pressure from the propane tank the gauge on the propane tankdoes not read anything. Like it isrunning less than 1 PSI. If I run thetank at 2 PSI then the main valve seems to work as designed, with adjustmentsand an inline gauge which make sense.
I have run the kiln twice and the first time it ran well,other than the aforementioned incompatibility of gauges. It used about 4-5 gallons of propane to getto cone 10 and it worked great. Thesecond firing went ok, but I failed to get up to temp before the propane ranout. The propane bottle froze up andjust wasted hours of propane without getting up to temp. I saw it happening as I was firing, butthought it would just keep up if I continually adjusted the tank pressure.
My question is that having said all of that I can convertover to natural gas and I think the kiln will run better. It is small so the feed to a single applianceshould be fine. I have a gas line withan extra shutoff within 25 feet of the kiln now so plumbing in a new line wouldbe easy. IS this the right way togo? Also how do I tell if the venture burnershave propane or natural gas orifices? Isuspect they are natural gas and I have been attempting to run high pressure propanewhich caused issues.
Posted 30 October 2012 - 05:00 PM
What type of kiln is it? A round top loading updraft?
Kiln Repair Tech
Owner, Neil Estrick Gallery, LLC
Posted 30 October 2012 - 08:30 PM
Also how do I tell if the venture burnershave propane or natural gas orifices? Isuspect they are natural gas and I have been attempting to run high pressure propanewhich caused issues.
I'm pretty sure (from the reasonably extensive research I've done) that natural gas venturi burners for kilns have #28 orifaces. You can get a #28 drill from your local hardware store. If it fits, it's a natural gas oriface. If it is too small for the #28 drill, it's a propane oriface. We had propane orifaces on our burners and drilled them out for natural gas. Yet to see how that works, but I've read it's no problem.
Posted 30 October 2012 - 08:49 PM
Your problems to me sounds like your kiln is set up for natural gas which has larger orifices- The valves will work with either fuel. If you want to stay with propane which costs more to run get smaller orifices. Unscrew the cast iron burn tips and use a small wrench to unscrew the brass orifice back by the air flow collar . Measure one with numbered drill
If you want to stay with natural gas and are close to a source. Have a line run-what size is the kiln in cubic feet? That will dictate gas pipe size as well as length of pipe run.
et us know what you find out.
Posted 30 October 2012 - 10:06 PM
The kiln is about 20 feet from the gas line. The main like seems to be 3/4 or 1 inch, but for the appliances it seems a 1/2 in pipe is the norm. I assume that the 1/2" pipe woudl work fine. That the the pipe size on the main fuel in on the kiln now.
Yes I can go down to SPS and purchase new orifaces if needed. I will disassemble one of the venturis and check the size with the Natural gas ones. They are only $6 each as far as I can tell.
The kiln is 10cf hexagon updraft. The guy told me it was a Crucible, but not real sure as there are zero makings on it.
To get the whole thing all setup for natural gas I think it it will be a little over $100 so worth the risk. Then i will have everything to run it on Propane or gas depending on how I need to configure it.
Yes ai understand it does freeze up, but I was so suprised how it froze slowly when teh tank was well over half full, and then the kiln just sucked the gas without getting much hotter. Perhaps it already has nartual gas orifaces, but will check.
Thanks for the help.
Posted 31 October 2012 - 01:45 AM
If it a crucible its made in Seattle if my memory serves. SPS can tell you everything about this kiln-take a photo of it and ask them.
My 12 cubic updraft has a 1/2 inch line for two feet before upsizing to larger 1 inch.
Is this a 4 burner model? 3 inch wall thickness?
Posted 31 October 2012 - 11:38 AM
Posted 31 October 2012 - 12:50 PM
Dave - Thanks for the information, I was not aware of that, as in the SPS catalog they call out only two orifices, one for propane and one for natural gas. Perhaps since this is a crucible kiln and SPS is the maker then these should be compatible.