Repair manual

CALIBRATION AND ADJUSTMENT
4-4
TEMPERATURE CALIBRATION - UNITED ELECTRIC CONTROLLER
NOTE: Th U.E. and Zytron boards get input from eiĆ
ther single or dual lead thermocouples.
LOW LIMIT ADJUSTMENT
1. Bring the oven to 200F (93C).
2. Turn both the blower and the heat switches to
OFF. The blower should continue to run.
3. Monitor the digital temperature control display.
The blower motors should shut off within the
range of 170Ć135Fāāā(77Ć57C).
4. To adjust the temperature, turn the lowĆlimit
potentiometer. A clockwise rotation increases
the setting, counterĆclockwise decreases it.
See FIGURE 6.
TEMPERATURE CALIBRATION
1. With the conveyor turned off, place a pyromeĆ
ter in the center of the oven cavity.
2. Adjust the set point for 500F (260C). Monitor
the Indicator Lamp. See FIGURE 6. When the
lamp goes out, compare the pyrometer with
the temperature of the display. If the display difĆ
fers by +/Ć5 F (3C), open the access panel
on the temperature controller and continue
with STEPS 3 and 4.
3. Adjust the Meter High Set so the display
matches the pyrometer. A clockwise rotation
lowers the display reading and raises the temĆ
perature. A counterĆclockwise rotation raises
the reading and decreases the temperature.
Check the oven set point. Adjustment of the
potentiometer may affect this reading. Bring
the oven up to 525F (274C). Verify the caliĆ
bration.
4. Set Point Adjustment Ć Adjust the Coarse ManĆ
ual so the controller calls for heat at 522 F
(272C) and shutĆoffs at 525F (274C). A
clockwise rotation raises the temperature,
counterĆclockwise lowers it.
HIGH LIMIT ADJUSTMENT
1. Turn both the blower and the heat switches to
ON.
2. Set the temperature to 620F (327C). When
the display reads 600 F (316C), the burner
blower motor should shut off. If the temperaĆ
ture rises above 600F (316C), adjust the hiĆ
limit pot (See FIGURE 6) so the burner shuts
off at 600F (316C). A clockwise rotation of
the highĆlimit pot increases the temperature,
counterĆclockwise decreases it.
NOTE: Repeat Low Limit Adjustment STEPS 1Ć3 to
verify new settings.
INCREASEDECREASE
INCREASE
1 2 3 4 5 6 7 8
230 115 NC C NO NO C
DECREASE
LOW LIMIT
HI LIMIT
United Electric Board
Panel
Flips Down
Coarse
Manual
Meter
High Set
Band
Width
Cycle
Time
Set Fully
CCW
Set Fully
CW
Lamp
Set Point
Temperature Control Board
ZYTRON
SERIES 300
13 26 5
478
115
230
NO C NC
OUTPUT 1
NO C
OUTPUT 2
T1
P1
LOW LIMIT
P2
HI LIMIT
P3
910
+
T/C
RED
INCREASE
DECREASE
DECREASE
INCREASE
Zytron Board
FIGURE 6