Operating instructions
Temperature Overshoot
When a kiln is heated too fast, it may overshoot the tar
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get temperature, especially in small kilns at lower tempera
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tures. To avoid this,add an extra segment toslow the firing.
The segment with the slower rate should begin approxi
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mately 40° - 60° below the final target temperature.
Starting a Firing in a Hot Kiln
Sometimes a firing begins in a hot kiln after a power fail
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ure or other interruption. In this case, the Sentry will begin
firing from the first segment that matches the current tem
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perature. See Power Failures, page 21.
AOP Fan
The optional AOP (auxiliary output) is a special-order
electric receptacle mounted in the kiln’s switch box. This
receptacle can power a kiln vent or external alarm. (See
Options, page 16.) During programming, will appear
for each segment ( etc.). Use the 1 and 2
keys to select On or Off for each segment. will ap
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pear only if the AOP has been activated in the AOP Op
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tion.
A Practice Program
To practice using the controller, we will enter a program
that includes three segments. The last segment is a cooling
segment.
Using the programming instructions on page 8, enter
this firing schedule. Thenuse Program Reviewto check for
accuracy.
USER = 1
RA1 = 250
°F1=750
Hd 1 = 00.00
RA2 = 900
°F 2 = 1425
Hd 2 = 00.30
RA3 = 150
°F3=750
Hd 3 = 00.00
RA4 = 0
Note: Enter 0 for the rate in segment 4. This zeroes
out all the segments past segment 3.
Chapter 3
Sample Firing
Programs
Thesesamplefiringschedulesillustratedifferentways
to program the Sentry. When designing a firing schedule
for materials you are unfamiliar with, or when using one of
these schedules, always test-fire samples first. This is be
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cause these generalized schedules may not exactly suit the
materials that you fire in your kiln.
For practice, you might want to enter these programs
even though you may never actually use them.
Heat Treating a Knife Made from
D-2HighCarbonSteel
Rate Temp.
Segment °F / °C °F / °C Hold
1 9999 1800 / 982 00.20
2 9999 400 / 204 00.00
3 500 500 / 260 5.00
Wrap the knife blade in heat treating foil. (The foil pre-
vents carbon scale from forming on the steel.)
Set the alarm to 1800°F / 982°C. Place the knife in the
kiln. Heat at FULL rate to 1800°F / 982°C. When the alarm
sounds, get ready to remove the knife. After 20 minutes of
hold time, open the furnace door, remove the knife, and
leave the door half open.
CAUTION: Wear high temperature heat-resistant
gloveswhen removing the knife blade from the furnace.
Removethebladefromtheheattreatingfoil.Placethe
knife on knifeholders, which allow air to circulate around
the blade. Place a fan several feet from the blade. Point the
blade toward the fan so the air flows parallel to the blade
length. Cool the blade rapidly to room temperature.
CAUTION: If the air hits the blades sideways, the
chance of warpage increases.
Leave the kiln door half open until the temperature
drops to 400°F / 204°C. Place the knife back inside the fur
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nace. Segment 3 will heat the kiln to 500°F / 260°C. Leave
the knife in the kiln for 2 hours. Remove the knife. Let it
cool to room temperature. Place it back inside the kiln for
another 2 hours. Then remove the knife.
Glass Fusing Firing Schedule
Rate Temp.
Segment °F / °C °F / °C Hold
1 250 / 138 750 / 398 00.00
2 900 / 500 1425 / 773 00.30
3 9999 / 9999 1050 / 565 00.00
4 150 / 83 750 / 398 00.00
10 Ramp-Hold
If you fire at a
very rapid rate,
the kiln may mo
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mentarily over
-
shoot the pro
-
grammed target
temperature. To
avoid that, use a
slower rate.