KB-130-7
12
After filling the system with liquid, remove filling
pipeline or filling hose and make sure that no liquid is
enclosed in it any more!
Permitted refrigerant
CO
2
of purity class N4.5 or comparable, or H
2
O
< 5 ppm.
The CO
2
purity class can have a higher H
2
O level if the
system is filled using a generously dimensioned filter
drier. It is recommended to change the filter drier sev-
eral times after commissioning.
Due to the high requirements regarding residual mois-
ture, a filter drier is required when filling with CO
2
of
quality level N3.0!
Filling process
◦ Do not switch on the compressor.
◦ Switch on the oil heater.
◦ Do not start the charging process until the following
oil temperature has been reached: min. t
oil
= t
amb
+
20 K. Ideally at 35°C .. 40°C.
• Use a pressure reducer and flexible filling pipelines
to connect the CO
2
refrigerant bottle to the service
connections of the system (suction and high pres-
sure side). Before tightening the screwed joints, flush
the pipelines with CO
2
vapour.
• Open the valves of the charging connections and
break the vacuum with CO
2
from the gas phase of
the filling cylinder until an overpressure of approxim-
ately 10 bar is reached. If the temperature of the re-
frigerant bottle is too low, it should be heated in a
water bath (water max. 40°C).
!
!
NOTICE
If the system pressure exceeds 10 bar, make
sure that the suction and discharge shut-off
valves of the compressor(s) are closed.
For booster systems: compressors of the me-
dium temperature and low temperature stages
are concerned.
The following work steps until commissioning may differ
depending on the system type.
6.2.1
Single stage systems without intermediate
pressure receiver
• Continue to fill the system with gaseous CO
2
up to a
maximum pressure of 40 bar.
• Make sure that the solenoid valves on the com-
pressor are closed (de-energised).
• Start the manual operation of the ventilators/water
supply for gas cooler.
• Continue to fill the gas cooler with liquid CO
2
.
• Further proceeding, see chapter Compressor start,
6.2.2
Single stage systems with intermediate
pressure receiver
• Continue to charge the system with gaseous CO
2
.
• If the system pressure exceeds 20 bar, make sure
that the solenoid valves on the compressor are
closed (de-energised).
• Start manual operation of the ventilators/water sup-
ply for the gas cooler.
• Continue to charge the intermediate pressure re-
ceiver of the system with liquid CO
2
(the minimum li-
quid level in the container should be reached).
!
!
NOTICE
If the pressure in the intermediate pressure re-
ceiver exceeds 30 bar, stop charging refriger-
ant!
Parametrise the system controller so that the
flash gas bypass valve of the first compressor
opens!
• Further proceeding, see chapter Compressor start,
6.2.3
Medium temperature and low temperature
booster systems
!
!
NOTICE
Observe the different maximum allowable pres-
sures of compressors and components used in
medium and low temperature stages.
If system pressure exceeds approx. 10 bar, en-
sure that the suction gas and discharge gas
shut-off valves in medium and low temperature
stages are closed!
• Make sure that the solenoid valves of the evaporator
in the low temperature stage are closed (de-ener-
gised).
• Continue to charge the medium temperature stage
with gaseous CO
2
.
• If the system pressure exceeds 20 bar in the me-
dium temperature stage, ensure that the solenoid
valves at the evaporator are shut (de-energised)
• Start manual operation of the ventilators/water sup-
ply for the gas cooler.
