Sheldon SHEL LAB SVAC1, Installation And Operation Manual, Page: 53 / 78

53 | P a g e
MAINTENANCE
C
ALIBRATING THE
T
EMPERATURE
D
ISPLAY
Note: Performing a temperature display calibration requires a temperature reference device. Please
see the
33T
Reference Sensor Devices entry
33T
on page 10 for device requirements.
Temperature calibrations match the temperature display to the actual chamber temperature inside
the oven chamber. The actual chamber temperature is supplied by a reference sensor device.
Calibrations compensate for software drifts in the controller as well as those caused by the natural
material evolution of the sensor probe in the chamber space. Calibrate as often as required by your
laboratory or production protocol, or regulatory compliance schedule. Always calibrate to the
industry or regulatory standards required for your application.
A Suggested Calibration Set-Up
1. Introduce the reference device vacuum-rated
thermocouple probe feedthrough into the KF-25
port on the back of the oven.
•
There must be at least 12 inches (305
mm) of wire in the chamber to prevent
heat sinking, which would result in a
false low temperature reading.
2 . Position the probe in the chamber.
•
Place the probe head as close as
possible to the geometric center
point of the chamber.
•
The probe head must be in direct
contact with the shelf surface.
3. Secure the probe head in position with
the non-marking, heat-resistant tape.
4. Use the KF-25 clamp to secure the
feedthrough and seal the port.
5. Close and latch the oven door. The door must
be sealed to carry out an accurate calibration.
6. Evacuate the chamber to the vacuum level of
your application or baking process. The
chamber must be under vacuum to perform an
accurate calibration.
Use non-marking, heat-resistant polyamide tape to
hold the thermocouple probe in place. The oven
manufacturer recommends Kapton brand tape,
0.5 inches width (12.7 mm), 2 mil thickness.
Probe head in direct contact with the shelf surface