asim mahmood on wed 23 apr 08
On last weekend, while doing glaze firing at cone 6 in my Skutt =
818- 240V kiln (done approximately 40 cone 04 and Cone 6 firings in the pa=
st 7 years and still in a good condition ) I was utterly disappointed as it=
did not reach to its required cone 6 temperature. Once it malfunctioned I =
was around my kiln and through the spy hole I could see the cone 5 (witness=
cone) completely bending down to 9 0=92 clock position and witness cone 6 =
standing still and kiln temperature constantly dropping down.
Initially, I thought that there was some thing wrong with the py=
rometer, giving incorrect reading so I gave some extra time but temperature=
kept dropping. I then manipulated with two of its infinite switches that t=
oo did not work. I finally hooked off the kiln momentarily and again plugge=
d it by putting the kiln in same gear but all in vain. Despite giving more =
time its sitter also did work and as a last resort I had to plug off the =
kiln.
On cooling down I off loaded the kiln, the glazing which was mostly of =
blue glaze was marginally ok but not of desired standard. The sitter and wi=
tness cone both were in their original shape except their color had turned =
white.
To ascertain the cause I once again switched on the kiln by turning on=
the upper infinite switch at low and as usual it responded by heating the =
connected upper elements and producing familiar buzzing sound indicating re=
lays in action. I then switched off this switch and turned on the lower inf=
inite switch but there was no response neither by heating the lower element=
s nor by creating familiar buzzing sound however the power indicator light =
located adjacent to it remain lighted during this test. According to my ass=
essment there are two possibilities either lower infinite switch has packed=
up or lower elements have given up.
I have gone through the clay art archive and Skutt web site, both do th=
rough light as to how to change the elements but are silent with regards to=
replacing infinite switch and its testing. I have been repairing my studio=
equipment at my own by consulting clay art or its archive and making my wa=
y through successfully. Once again I am looking forward for your advice on =
the followings:
1. What are the possible causes of this malfunctioning?
2. What kind of tests I should conduct to pin point the problem? (I do hav=
e all necessary test equipment)
3. Incase there is a problem with lower elements then is it necessary t=
o replace the upper ones?
4. Incase the lower infinite switch is faulty is it necessary to replac=
e the upper one.=20
5. I am with average intelligence and self taught potter therefore need=
step by step repairing procedure or references to go to. =20
=20
Let me thank you all in advance. Regards,
Asim Mah=
mood =20
_________________________________________________________________
Spell a grand slam in this game where word skill meets World Series. Get in=
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08=
Arnold Howard on thu 24 apr 08
From: "asim mahmood"
1. What are the possible causes of this malfunctioning?
2. What kind of tests I should conduct to pin point the
problem? (I do have all necessary test equipment)
3. Incase there is a problem with lower elements then is
it necessary to replace the upper ones?
4. Incase the lower infinite switch is faulty is it
necessary to replace the upper one.
-------------
Asim, a switch has probably burned out. Get a wiring diagram
for your kiln. Take some time to study it, and it will
answer many questions, because it is a map of the kiln's
switch box. It will show you how the elements are connected
to each switch. An ohmmeter test should pinpoint the
problem.
I would not replace all the elements unless they were
already near the end of a wear cycle. I would replace only
the one that burned out. I would also replace only the
switch that burned out.
The problem may be as minor as a burned out wire, though.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
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