Eppendorf R Series 48R CO2 Incubator - Manual (Page 55)

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New Brunswick Scientific User’s Guide
8.5.9 Troubleshooting the Oxygen Sensor
If the oxygen sensor fails suddenly, it is very likely that the sensor inlet
membrane has become blocked by condensation. This can be seen on the
DATALOGGER screen as a sudden drop from the programmed value to nearly
zero.
To dry the membrane:
1. Remove the hydrophobic filter holder assembly (see Figure 22) by
unscrewing it (counter-clockwise).
2. Program the incubator for a temperature of at least 37°C (or higher if you
normally operate the incubator at a higher temperature).
3. Close the door and allow the temperature to recover.
4. Reopen the door for 15 seconds to release any build-up of humidity.
5. Repeat steps 3 and 4 every 30 minutes or so, keeping an eye on the
DATALOGGER O
2
Graph. The oxygen level should rather suddenly
recover after a few hours.
6. Leave the incubator for a few more hours to be sure that the sensor
membrane has thoroughly dried out.
7. Replace the hydrophobic filter disc following the instructions in Section
8.5.8.
8. Re-humidify the incubator.
9. After 2 or 3 hours, carry out an OXYGEN SENSOR-REF TO
ATMOSPHERE procedure. When the referencing has been successfully
completed, the incubator is ready for use.
8.5.10 Oxygen Control Specifications
The Oxygen Control option has the following characteristics:
Sensor Type
Self-powered, diffusion-limited, electrochemical
cell with temperature compensation.
Zero Signal in Nitrogen
< 50 μV
Temperature Compensation
± 2% of signal variation from 0-40°C
Relative Humidity Range
0-99%, non-condensing
Operating Temperature Range
-20°C to +50°C
Resolution
0.01% Oxygen
Expected Operating Life
1-2 years in ambient oxygen
Hydrophobic Filter Operating
Life No data available on the filter lifespan but we are
confident to expect it will last at least 6 months.
Nitrogen Input Rate 20 l/min at 1 bar (14.5 psi)
Typical Oxygen Reduction
Rates
3 minutes to 16%
4 minutes to 11%
8 minutes to 6%