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APPENDIX 1 : REFRIGERANT AND OIL CHARGING
This appendix gives the instructions for charging the unit with R744 and additional oil.
The following assumptions have been made in order to calculate both charges:
-
90% filling factor for gascooler in partload.
-
Min/Max level in receiver: 10% / 80%.
-
Liquid line and suction line diameter following the specifications page 63.
-
20% filling factor for the evaporator.
Here's an example of how to determine the required charges:
-
In this case, an MT67 unit has to be installed with a 7dm
diagrams gives the corresponding R744 and oil charge :
-
Start on the crossing point of the unit (MT67) and the length of the pipe (20 meters),
-
Draw a horizontal line from this point which crosses the evaporator volume line,
-
Draw a vertical line from the crossing point of both lines and read both CO2 charge (at the bottom)
and additional oil charge (at the top).
-
In this particular example, the R744 charge equals 7.8 kg and an additional oil charge of 60 mL is
required.
The installer also has to consider the zone of this crossing point for charging restrictions:
-
Green zone : No restrictions
-
Yellow zone :
overfilled and cause compressor damage by liquid floodback. Close the liquid line valve to avoid this
issue.
-
Red zone :
The diagrams for the different models are shown in the next pages:
Warning
: Do not pump down the liquid line into the unit, or the receiver could be
Not
allowed.
3
evaporator and a 20m pipe. The following
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