Kendro HERAcell 150, Operating Instructions Manual

Page: 67 / 251

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Incubator HERAcell ® 150 Operating Instructions
67
Fig. 28
Temperature calibration
10. Maintenance
10.3 Preparing the temperature calibration
To determine the exact measured value of the device-integral
temperature sensor, a temperature comparison measurement
has to be performed every three months.
If a major temperature deviation is found during this check, a
temperature calibration is required.
During this process, the temperature control of the device is
set to the value measured during the temperature comparison
measurement.
Use a calibrated measuring instrument with an accuracy of
± 0.1° C for this test. To minimize temporary temperature fluc-
tuations during the measurement, the measuring instrument
is placed into the work space in an isothermal container (e.g.
a bowl filled with glycerol). The center of the work space is the
reference location for the comparison measurement.
NOTE – Isothermal container
Do not use a container filled with water as an
isothermal container as the evaporation of
water will result in a lower temperature reading.
Comparison measurement procedure:
1. Turn device on using power switch.
2. Set temperature nominal value and allow device to be hea-
ted. This may take up to several hours.
3. Fig. 28: Place measuring instrument [3] onto the center area
of the work space.
Alternatively, a temperature sensor may be positioned in
this location. Route the connecting cable either through the
measurement opening [2] in the glass door or through the
access port [1] at the rear panel of the device.
4. Close doors.
5. Wait until the temperature value displayed at the measu-
ring instrument has stabilized.
6. Calibrate temperature control as described in Section 10.4.
Measurement example:
• Temperature nominal value: 37° C
• Reference temperature: 36.4° C
NOTE – Excessive work space temperature
Excessive work space temperature after the ca-
libration can be reduced by leaving the doors
open for approx 30 seconds.