Checking The Temperature; Fig. 24 Temperature Equalization - Kendro HERAcell 240 Operating Instructions Manual

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HERAcell 240 CO Incubator Operating Instructions
2
11. Maintenance

11.3 Checking the Temperature

In order to determine the precise value being measu-
red by the internal temperature sensor, a comparative
temperature measurement should be performed
quarterly.
If the result indicates a measured value deviation of
> 0.2 °C, a temperature equalization should be per-
formed.
For this, the unit's temperature control is adjusted to
the measured value obtained in the comparative mea-
surement.
A calibrated instrument with an accuracy of ≤ ± 0.1 °C
should be employed for the comparison. To minimize
temperature fluctuations during the course of the
measurement, immerse the temperature probe in an
isothermal container (e.g., a beaker filled with glyce-
rin).
NOTE – Isothermal container:
A container filled with water must not be used
as an isothermal container as the water's evaporation
will cause the instrument to indicate a temperature
that is below the actual temperature.
Performing a Comparative Measurement:
1. Switch the incubator on at the main power switch.
2. Define the temperature setpoint, then wait until
the unit temperature has stabilized. This may take
several hours.
3. Place the isothermal container with the instrument
[3] on the center of the insert tray located in the
middle of the sample chamber.
Alternatively, a temperature sensor can be posi-
tioned in the same location. The sensor line can
either be passed through the measurement
opening [2] in the glass door or through the
access port [1] on the back of the unit.
4. Close the doors.
5. Wait until the instrument temperature reading is
constant.
6. If the temperature deviation is > 0.2 °C, calibrate
the temperature control accordingly. Refer to the
steps in Table 11.4.
Measurement Example:
•
Temperature setpoint: 37° C
•
Comparison temperature: 36.4° C
Version: 03.2001 / 50065640
Figure 24
Fig. 24, Temperature equalization
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