Manage Superheat - Danfoss DSH090 Application Manual

Scroll compressors, DSH090 to DSH600 | Application
System evaluation
HP and LP must be monitored to respect operating envelope limitation. We consider two types of operating
envelope management: Basic and Advanced.
Table 28: System evaluation
Basic
• HP and LP switch
• MOP (Max Operating Pressure) ensured by expansion device
• Condensing pressure control
• DGT external setting points: R410A max 135°C (275°F), R454B/R452B max
150°C (302°F)
HP switch setting
CC-000166
Condensing pressure control

Manage superheat

During normal operation, refrigerant enters the compressor as a superheated vapor. Liquid flood back occurs when
a part of the refrigerant entering the compressor is still in liquid state.
Liquid flood back can cause oil dilution and, in extreme situations lead to liquid slugging that can damage the
compressor.
Requirement
In steady state conditions the expansion device must ensure a suction superheat within 5K to 30K (9 to 54°F).
System evaluation
Use the table in relation with the application to quickly evaluate the potential tests to perform.
Table 29: System evaluation
Application
Non reversible
Reversible
© Danfoss | Climate Solutions | 2022.10
Advanced
• HP and LP sensor
• Operating envelope limits integrated into control logic
• Temperature measurement (monitoring by sensor)
Whole operating envelope limits integrated into control logic
CC-000192
Tests to perform
Liquid flood back test
Liquid flood back test
Defrost test
AB288965961751en-001402 | 48