Manage off cycle migration
R
Requirement
Evaluate the risk
Off -cycle refrigerant migration happens:
•
when the compressor is located at the coldest
part of the installation, refrigerant vapor
condenses in the compressor.
•
or directly in liquid-phase by gravity.
When the compressor starts running again, the
refrigerant diluted in the oil generates poor
lubrication conditions. In extreme situations,
this leads to liquid slugging that can damage
compression parts.
Amount of liquid refrigerant in the compressors
must not overpass the charge limit (refer to
charge limit table in section “Manage superheat”).
Use the table below in relation with the system
charge (refer to charge limit table in section
“Manage superheat”) and the application to
quickly define necessary safeties to implement
and test to perform:
BELOW
cHargE
Limit
aBOVE
cHargE
Limit
Non split
No test or additional safeties required
(Internal Non-Return Valve integrated)
• Crank Case Heater*
• Migration test
• External Non Return Valve
Split
Since each installation is unique, no test can fully evaluate off-cycle migration, therefore
the following safeties are required:
• Crank Case Heater *
• Liquid Line Solenoid Valve**+ pump-down cycle***
• (Internal Non-Return Valve integrated)
33
FRCC.PC.012.A7.02
GENER
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ATION
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ODUC
T INFORM
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ATION INT
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