Temperature Calibration - Blodgett MT3255 Series Service And Repair Manual

MT3255 and MT3270

TEMPERATURE CALIBRATION

TO ENTER THE CALIBRATION MODE
1. Press the ON/OFF key until OFF is displayed.
2. Press CLEAR 1 2 3 4 5 6 ENTER to enter the
access mode. The display reads ACCESS.
3. Press CLEAR
ACT_TEMP ENTER to access the Temperature
Calibration mode.
4. Disconnect the white wire from the D.C. motor.
Secure so the wire will not ground against any
part of the oven. This will disable the conveyor.
NOTE: Disregard the controller display. The only
numbers of concern are the pyrometer
reading and the temperature set point.
TO CALIBRATE THE OVEN TEMPERATURE
During operation, the temperature control is based
on the measured temperature and the tempera-
ture offset which is programmed into the control. If
the temperature measured in the center of the
oven is below the oven setpoint a positive offset is
needed. If the temperature measured in the center
of the oven is above the oven setpoint a negative
offset is needed.
NOTE: In the calibration mode the display gives
the current measured temperature only.
To view the current temperature setpoint:
1. Press the SET_TEMP , key.
To change the temperature setpoint :
1. Press PROG/ENTER SET_TEMP .
2. Enter the desired setpoint.
3. Press the PROG/ENTER key.
To program the temperature offset:
To change the temperature calibration an offset,
positive or negative, must be programmed.
ACT_TEMP ACT_TEMP
1. Press PROG/ENTER followed by ACT_TEMP .
The display flashes either POS * OFFSET or
NEG * OFFSET
NOTE: POS OFFSET is displayed if a value has
been programmed in for a positive off-
set. NEG OFFSET is displayed if a val-
ue has been programmed for a nega-
tive offset. The only time both will be
displayed is if a value of 0 has been en-
tered for both.
2. Enter a value for the desired offset. The display
flashes DISPLAY * INTEG?.
3. Press the PROG/ENTER key. The default value
of 30 will be displayed.
4. Press the PROG/ENTER key. The display will
flash T-CTRL * INTEG?.
5. Press the PROG/ENTER key. The default value
of 10 will be displayed.
6. Press the PROG/ENTER key.
The control will now resume using the new param-
eters.
Verify the temperature calibration once the unit has
cycled for 5 minutes with the new settings. Repeat
calibration using a new offset value if necessary.
TO EXIT THE CALIBRATION MODE
1. Press the CLEAR key twice.
2. The display flashes REBOOT then displays the
set time and temperature. You must re-enter a
temperature for the oven to start heating again.
A.) Press PROG/ENTER SET_TEMP
B.) Enter the desired temperature.
C.) Press the PROG/ENTER key. The heat
light turns on and the burner begins to
cycle at set point.
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