PGW40
Operator Manual
14 September 10, 2020 | 296742-ENG R00
3.13.2 Adjusting the CO
2
Control
There are two variables to consider: programming desired CO
2
concentration and control of air
flow through the chamber.
Programming the CO
2
setpoint is as easy as programming temperature or relative humidity.
Values are entered in parts per million (PPM) in the CO
2
zone on the Main Status Program Screen
of the Controller. The Vaisala™ CO
2
monitor operates in two ranges, up to 2000 ppm and up to
3000 ppm.
Ambient CO
2
levels are usually at least 350 ppm and can be higher depending on proximity to
other CO
2
sources such as human beings or automobiles. The CO
2
concentration in the chamber
can never be less than the ambient concentration because CO
2
control is additive only.
Closing fresh air into and exhausting air out of the chamber is important to achieving desired CO
2
concentrations. Failure to consider this will lead to undesired results. New chambers with CO
2
control are equipped with an automated damper to control airflow, older chambers will have
manual ports. These units will also typically have a manual fresh air inlet and exhaust outlet for
running programs without CO
2
control. Some chambers are only equipped with the manual inlet
and outlet.
Refer to the included
Conviron CMP6060 Op
erator’s Manual
for complete instructions.
3.14 Central Management System
– CMS Option
Refer to the included
Conviron CMP6060 Operator’s Manual
for complete instructions.
3.15 Shutdown
In the event that the chamber will not be used for two weeks or less, it is best to keep it running,
with the temperature at or near ambient and only the fans running.
If experiments will not be run for more than two weeks, to minimize unnecessary electricity
consumption, ensure all plants and soil are removed from growth area, clean the unit as described
in Section 4 Maintenance, starting on page 15, and leave the chamber and observation doors
open slightly to reduce moisture buildup.
The exhaust damper also serves to purge CO
2
in the event of a high-level CO
2
alarm.
If the high CO
2
limit is set below the CO
2
setpoint, the exhaust damper will open to
purge CO
2
to the surrounding space.
