Don Kopyscinski on thu 9 may 96
Hi Kat,
> The end of my sensing rod is all black and crusty -- make that my Skutt
KILN'S sensing rod -- and I'm guessing this might affect how the kiln fires.
So, how difficult is it to replace the tube and rod and all that stuff? <
I'm on about my 25th sensing rod. This is a normal wear item and can be quite
simple to replace. I have seen sitter systems designed well enabling you to
replace the rod with maybe 9 screws total and a terrible configuration that
forced me to remove the whole sitter box and take it apart to get at the rod. If
you can get the old one out, there is no reason not to replace just the rod
(cost around $2.50) as opposed to the tube assembly (about $20.00) [that's if
the set screw on the collar that holds the rod will cooperate.
If you have an easy set-up, you do the following (if you can't see how the tube
will come out in step 5....dust off those manuals, or get Skutt or Dawson on the
phone - both very helpful).
1-Breaker off.....unplug kiln,
2-remove two screws holding the guide plate (metal plate with slot that the rod
moves up and down in) to sitter.
3-remove the two screws holding the tube assembly to the sitter (the tube
assembly will now move freely inside the sitter box)
4-remove the four screws that hold the black plate on the front of the sitter
box
5-carefully and slowly slide plate towards you moving it out and to the side
only enough to be able to slip out the tube assembly (cone removed). (It is here
that brittle wire insulation could cause need for replacement ,and a quick fix
turned into a bigger job, but if your kiln was designed correctly the wires
shouldn't be too brittle) Slow and easy! If the wires to the timer (if so
equipped) are short and stopping you from moving that plate to the side, you may
need to remove the knob from the timer, take the timer off the plate and
proceed.
6-once the tube assembly is out, there is a small set screw in a ring that holds
the rod in place. Loosen the set screw, remove and replace the rod (make sure
you've got the correct length for your kiln). Tighten the rod making sure the
rod is lined up at one end to just before (1/16") the end of the cone supports
(those two metal prongs that the cone rests on - these may also be replaced if
needed, at about $1.50 for the pair). Using just the right sized screwdriver
will help here and perhaps some liquid wrench or similar penetrating oil (a dab
of anti-sieze in the hole before you replace the screw will make the next time
easier). This part is sometimes trouble as that darned set screw is too tight
and you can't get it out, sometimes stripping the screw. If you just can't get
the rod out, then a tube assembly replacement is in order (anti-seize now, be
glad later).
7-once rod is replaced re-insert tube carefully not to damage brick
8-reverse the order (you remember which screws go where..... right?)
9-use sitter alignment plate (that disk with a hole that came in the sitter) to
re-align sitter. Adjust moving plate in weight so that it just barely clears the
hook with the disk in place (on cone supports, rod through center hole).
10-before plugging the kiln back in, use a multimeter to check for proper ground
(you should get continuity touching ground and all three rings (the jacket of
the kiln, and you should not get it touching either hot leg (try both) and all
three rings.....if you do, this would signal a short)
11-REMEMBER- A sitter is not designed as a shut-off device for the kiln....it's
made as a safety back-up in the event you "the firer of the kiln" failed to do
your job properly for some reason. They are not foolproof, they can and do fail
to shut a kiln off (once in a thousand....you feeling lucky???).
It's really one of the easier fixes for an electric kiln,
Don Kopyscinski
Bear Hills Pottery
Newtown, CT
Who likes to have a few spare parts on hand.
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