CIRAS-3 Operation Manual V. 1.09
193
H
2
O Calibration
For H
2
O calibration, an air supply of known water vapor concentration is required (mb). Refer to
on page 100 for instructions. Typically this is achieved using a commercially available
humidity generator or water vapor generator. If you do not have a device for H
2
O recalibration, please
contact PP Systems and we will be happy to recommend some. PP Systems can also perform H
2
O
recalibration services at our factory.
PLC3 Leaf Cuvettes
Cuvette Gaskets
The most common part requiring routine inspection and replacement are the leaf cuvette gaskets. This is
also the place where leaks are often discovered leading to fluctuations in CO
2
and H
2
O readings. Over
time, plant material can cause the gasket material to crack or even deform requiring replacement.
Leaf gaskets can easily be removed using a fine screwdriver to pry them out of their respective channels
in the cuvette head. Open the leaf cuvette head as shown above and using a fine screwdriver and gently
pry the worn gasket material from the head. Take care to remove all debris, old gasket material or
anything else that will prohibit you from clean replacement of the new gaskets. Peel the new gasket from
the white backing and carefully place it in the appropriate location on the cuvette head and seal it in
place. We recommend applying a very light smear of silicone grease to preserve the gaskets and to
provide a good seal.
Upper head gasket
Lower head gasket
Rear gasket
