CO
2
Incubator BB 150 Operating Instructions
56
10.
Maintenance
10.5
Preparing the CO
2
calibration
To determine the exact measured value of the device-integral CO
2
sensor, a CO
2
comparison measurement may be performed
every three months.
If a major deviation is found during this check, a CO
2
calibration
is required.
During this process, the CO
2
control of the device is set to the
value measured during the comparison measurement.
Use a calibrated measuring instrument with an accuracy of
≤≤≤≤≤
± 0.3 % CO
2
for this test.
Suitable instrument:
• Portable IR readout instrument. (Part no. see Section 11,
“Spare parts and accessories”)
The measuring sample is withdrawn through the sealable mea-
surement opening of the glass door. The comparison measu-
rement must be performed when the device is completely stable.
Comparison measurement procedure:
1. Turn device on using power switch.
2. Set CO
2
nominal value and allow device to heat up com-
pletely and to create humidity. This process may take se-
veral hours.
3.
Fig. 24:
Insert the measuring instrument probe through the
measurement opening [1] into the work space. Wait until
the CO
2
value displayed by the instrument has stabilized.
4. Remove measuring probe, plug measurement opening and
close doors.
5. Calibrate CO
2
control as described in Section 10.6.
Measurement example:
• CO
2
nominal value:
5 %
• Measured value:
5.6 %
NOTE – Excessive CO
2
content
Excessive CO
2
content after the calibration can
be reduced by leaving the device doors open
for approx 30 seconds.
Fig. 24
CO
2
calibration
