Forma Series II 3110 Water-Jacketed co2 Incubators User Manual

Water Jacketed CO
2
Incubator        2-1
Thermo Scientific
Section 2  
Calibration
After the unit has stabilized, several different systems can be calibrated. In
the Calibration Mode, the air temperature, CO
2
reading, O
2
reading, and
RH reading can all be calibrated to reference instruments. To enter
Calibration Mode, press the Mode key until the CAL indicator lights. Press
the right and/or left arrow until the proper parameter appears in the
message center. See Chart 2-1 for more detail.
Calibration frequency is dependent on use, ambient conditions, and
accuracy required. Good laboratory practice would require at least an
annual calibration check. On new installations, all parameters should be
checked after the stabilization period. When using O
2
controls, all
parameters should be checked before each test experiment, or at least every
6 months.
Prior to calibration, the user should be aware of the following system
functions. While the unit is in Calibration Mode, all system control
functions will be stopped so that the unit remains stable. Readout of the
system being calibrated will appear as “—-” on the readout displays. If no
keys are pressed for approximately five minutes while in Calibration Mode,
the system will reset to Run Mode so that control functions can be
reactivated.
Before making an calibration or adjustments to the unit, it is imperative
that all reference instruments be properly calibrated.
Place the calibrated instrument  in the center of the chamber. The
instrument should be in the airflow, not against the shelf.  Before
calibration, allow the cabinet temperature to stabilize.  
Calibrating the
Temperature

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Calibrating T/C CO
2
System
2-2
Water Jacketed CO
2
Incubator
Thermo Scientific
Section 2
Calibration
Start-Up - Allow 12 hours for the temperature in the cabinet to stabilize
before proceeding.
Operating Unit - Allow at least two hours after the display reaches setpoint
for the temperature to stabilize before proceeding.
1. Press the Mode key until the CAL indicator lights.
2. Press the right arrow until TEMPCAL XX.X appears in the message
center.
3. Press the up/down arrow to match the display to a calibrated
instrument.
4. Press Enter to store the calibration into memory.
5. Press the Mode key to return to Run, or the right/left arrow to go to
the next/previous parameter.
Models 3110, 3111, 3130 and 3131 have a thermal conductivity (T/C)
CO
2
sensor. Thermal conductivity of the incubator atmosphere is not only
effected by the quantity of CO
2
present, but also by the air temperature
and the water vapor present in the incubator atmosphere. In monitoring
the effects of CO
2
, air temperature and absolute humidity must be held
constant so any change in thermal conductivity is caused only by a change
in CO
2
concentration. 
Changing temperature or changing from elevated humidity levels to room
ambient humidity levels would necessitate a recalibration of the CO
2
control. 
Some T/C CO
2
sensors go through an aging period, especially on new
installations. Calibration should be checked on a weekly basis, and adjusted
as necessary. When stabilization occurs, checks can become less frequent.
Temperature Stabilization
Periods

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Calibrating Infra-Red
CO
2
System
Water Jacketed CO
2
Incubator        2-3
Thermo Scientific
Section 2
Calibration
Start-up - The CO
2
sensor has been calibrated at the factory for 37°. Allow
temperature, humidity, and CO
2
levels in the chamber to stabilize at
least 12 hours before checking the CO
2
concentration with an independ-
ent instrument.
Presently operating - Make sure the chamber doors are closed. Allow at
least 2 hours after the temperature and CO
2
displays reach their set-
points for chamber atmosphere stabilization. 
1. Make sure stabilization periods outlined above are followed.
2. Sample the chamber atmosphere through the sample port with an
independent instrument. Sample the atmosphere at least 3 times to
ensure the accuracy of the instrument.
3. Press the Mode key until the CAL indicator lights.
4. Press the right arrow until CO2 CAL XX.X is displayed in the message
center.
5. Press the up/down arrow to change the display  to match the
independent instrument.
6. Press Enter to store calibration.
7. Press the Mode key to return to Run Mode, or the right or left arrow
keys to go to the next/previous parameter.
Models 3120, 3121, 3140 and 3141 have an infra-red CO
2
sensor. Infra-
red CO
2
sensors are not effected by chamber atmosphere temperature or
humidity. However, the light detector in the sensor is effected by wide
temperature changes. Therefore, changing temperature setpoints could
necessitate a recalibration of the CO
2
. Chamber temperature should be
allowed to stabilize before checking CO
2
concentrations with an
independent instrument, especially on start-up.
All models equipped with an IR/CO
2
sensor have an automatic calibration
that occurs every 24 hours, and lasts for 5 to 6 minutes. During automatic
calibration, the CO
2
display is blanked out and HEPA filtered room air is
pumped through the CO
2
sensor. A new CO
2
calibration value is stored in
memory for use as the 0.0% CO
2
reference point. The keypad/ control
panel is locked during calibration, with the message center reading CO2
AUTO CAL.
T/C CO
2
Sensor
Stabilization Periods

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