Danfoss DSH090 Application Guide

Dilution Chart - DSH240 to DSH600 R410A/ R452B / R454B
Figure 56: Dilution Chart (reference at 20°C / 68°F ambient temperature)
15
12.5
10
7.5
5
-25-30 -20 -15 -10 -5 0 5 10 15 20 25
-13-22 -4 5 14 23 32 41 50 59 68 77
2.5
0
27
22.5
18
13.5
9
4.5
0
CC-000026
Evaporating Temperature (°F)
Safe Area
Unsafe Area (60 sec max per hour)
Evaporating Temperature (°C)
Oil Superheat (K)
Oil Superheat (°F)
Manage o cycle migration
O -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 or pressure dierence. When the compressor restarts, the refrigerant diluted
in the oil, or stored in evaporator, generates poor lubrication conditions, and may reduce bearings life time. In
extreme situations, this leads to liquid slugging that can damage the compressor scroll set.
Requirement
• Compressor can tolerate occasional ooded start, but it should remain exceptional situation and unit design must
prevent that this situation happen at each start.
• Right after start, liquid refrigerant must not ow massively to compressor
• The charge limit is a threshold beyond some protective measures must be taken to limit risk of liquid slugging and
extreme dilution at start.
System evaluation
Use the table below in relation with the system charge and the application to quickly dene necessary safeties to
implement.
Table 31: System charge
Application
BELOW charge limit
ABOVE charge limit
All
Ensure tightness between condenser & evaporator when system is OFF
• Thermostatic expansion Valve (TXV) , Liquid Line Solenoid Valve LLSV strongly recommended
• Electronic expansion valve (EXV) must close when system stop including in power shut down situation
Non split
No test or additional safeties required
• Crankcase heater
Split
Since each installation is unique, refrigerant charge may vary
• Crankcase heater
• Liquid Line Solenoid Valve+ pump-down cycle
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Scroll compressors, DSH090 to DSH600 | Application

Danfoss DSH090 Specifications

General

Brand	Danfoss
Model	DSH090
Category	Air Compressor
Language	English