the wall where the thermocouple tip appears in the firing chamber. Be sure to unplug the kiln before removing
switch box.) The screws in the ceramic block must be tight.
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Is the thermocouple touching the metal case of kiln?
That can cause erratic temperature readings. Remove switch box to inspect.
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How far off is the temperature?
Ceramics: Pyrometric shelf cones are the best calibration standard for ceramic firings. If all your cones consistently
under- or over-fire, adjust the Controller temperature using the methods below. Use witness cones in every firing.
Keep a record of every firing. Blank firing records are available from Paragon.
DTC 1000 Cone-Fire: Use cone offset to adjust the temperature for each individual cone. Or use thermocouple
offset to adjust the temperature for all the cones.
DTC 1000 Ramp-Hold: Use thermocouple offset to adjust the controller temperature.
DTC 800C: Use Fine Tuning to adjust the cone temperature.
DTC 800: Enter a temperature that will compensate for the thermocouple temperature drift.
DTC 600C: Enter a different cone number, or use hold, to compensate for temperature drift.
DTC 600 & 100C: Enter a temperature that will compensate for the thermocouple temperature drift.
The kiln overfires.
See “Controller reads wrong temperature,” page 10.
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Do the elements stay on after you press STOP?
If so, the electrical contacts inside a relay are stuck in the closed position. Replace relay. See “Relay 12 Volt Battery
Test,” page 14.
The display shows erratic temperature readings.
It is normal for the temperature to jump up or down a few degrees during firing. As temperature rises, the readout
will not show a steady climb, but rather minor jumps up and down. This section of the troubleshoot is for readouts
that are erratic by 10 - 15 degrees and more.
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Does erratic temperature display start at around 1600°F?
A poor circuit ground can cause high temperature erratic readings. So can a thermocouple that touches a grounded
object such as the kiln case.
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Is temperature erratic only when the elements are on?
Power wires (cord-to-relay and relay-to-element wires) placed near the con
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troller and thermocouple wire cause this type of fluctuation. Fire the kiln to
around 600°F. Press STOP. This will shut off the elements. If the tempera
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ture display is no longer erratic at IdLE, try rearranging the wires inside the
switch box.
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Do the relays chatter? Does the temperature fluctuate in
time with the clicking of the relays?
A relay with a short in the electromagnet can cause an erratic display. The relay draws too much current, draining
voltage from the board and interfering with normal display. Another cause is a bad transformer that produces low
voltage. See “Controller Power Input Test,” page 4.
Electrical “noise,” which is random electromagnetic signals, can cause the controller temperature to become er
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ratic. Common sources of noise are a chattering relay, defective lid or door switch, and nearby arc welding ma
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chines. See “The relay chatters or buzzes,” page 12.
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Is the temperature display erratic at room temperature?
Perform the “Controller Paperclip Test,” page 13. If the display at room temperature is still erratic with the
paperclip in place on the back of the board, the thermocouple is not the cause.
11
The thermocouple lead wire shown here is too
close to the other wire.
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