Shellab SVAC9-2 - Manual (Page 21)

21 | P a g e
OPERATION (CONTINUED)
C ALIBRATING THE U NIT
The oven should be installed in its workspace environment when performing a temperature
calibration to ensure the best possible accuracy. Always calibrate the oven to the temperature that
will be
used in the oven’s application or process. If a multi-step heating profile will be used,
calibrate the oven to the temperature that will be used during the longest soak (constant
temperature) step.
1. Place the temperature sensor of a certified reference device inside the oven. A
potted sensor probe may inserted through the vacuum flange (K flange
assembly) on the back of the oven. Or a dial reference thermometer may be
placed on the center of the center shelf so that its display can be read through
the chamber door window.
Note: Always use an independently certified temperature reference device that is
regularly calibrated to 0.5°C accuracy or better to conduct temperature
calibrations or verifications.
2. Turn the Power Switch to the ON position. The oven will begin to heat. The set
point in the green midlevel display should be the temperature that the oven will
be used at during its next application.
3. Apply vacuum to the oven’s chamber at the same level that will be used at during the
oven’s next baking application or process.
4. Allow the chamber to heat to up the set point while under vacuum, and then stabilize with
no change in temperature for at least a-half hour (30 minutes) prior to performing the
calibration.
5. Read the reference temperature device’s display. Compare its reading with the
temperature shown in red at the top of the Watlow Controller’s screen.
6. If the reference device’s and the Watlow’s temperature readings are the same or fall within
the range of your laboratory or production protocol, the oven is now calibrated.
7. If there is a temperature difference between reference device and the Watlow, and that
difference falls outside your protocol ’s acceptable range, adjust the Watlow to match the
reference device’s reading by entering a temperature offset. See the next step.
Note: The accuracy of the calibration process is limited by the accuracy of your reference
temperature device.
Figure 8: Example of a potted
probe inserted into the Back
KF-25 Flange