Robert Edney on fri 6 oct 06
I just thought of something that may simplify the diagnosis:
As I recall, the Skutt controller has a manual function (you'd want
something like that for firing the occasional raku pot). Switch to manual
and full power -- however that translates in the controller's language.
Make sure all of the elements are glowing at the same color (easier with the
lights off at night). If they aren't, there is an element problem (bad
element or bad element connection or -- less likely -- a controller
problem). If they all glow, go to the next step:
Load the kiln with just enough furniture to get a cone pad adjacent to a
peep-hole at mid level. At full, _manual_ power fire the thing (it won't
take long at full power and with no pots inside) and see if you can get cone
6 to drop within a reasonable period of time (I'd use a 4,5 and 7 cone too).
If you can get 4 or/and 5 to drop but not 6 it would tend to confirm the
diagnosis of the elements just being wrong (being as we seem to have
established via the electrician sufficient power to the kiln), at which
point you replace them as previously recommended. If 6 will drop empty,
load the kiln as usual and repeat (manually adjusting temp just like you
would prior to controllers). If you don't want to risk pots, put some
rejects/shards/extra furniture in there to simulate a full load. If you can
drop cone 6 within a reasonable period of time fully-loaded manually but not
via the program, you have a controller problem. If you can't drop 6 fully
loaded, again this would indicate the wrong elements.
The big clue here is that you said that it _was_ working but now it's not.
What all of us technophiles have been missing is this simple fact. The most
likely culprit is a bad or marginal element or two for sudden failure like
this. If it would fire to 6 before but slowly (as you said) that would
indicate that the elements could do it when brand new, but not now. Again,
new, voltage-correct elements.
One last note: You indicated that you have two kilns in the studio.
Electrical service sufficient for one is not necessarily sufficient for two.
For simplicity sake lets say you have two kilns that each draw 50 amps. To
run both you'd need at least 100 amps of service dedicated to just the
kilns. You could get away with 50 amps of service if you only ran one kiln
at a time however (one cooling while the other fires).
Simple and direct?
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