HP
3
3
2
2
5
4 m*
4 m*
6
6
6
1
LP
4
CC-0043
1
2
3
4
5
6
*
Evaporator
0.5% slope
4m/s or more
8 to 12 m/s
To condenser
U-trap, as short as possible
Max.
Suction lines
If the evaporator lies above the compressor, as is often the case in split or remote condenser systems, the addition of
a pump-down cycle is strongly recommended. If a pump-down cycle were to be omitted, the suction line must have
a loop at the evaporator outlet to prevent refrigerant from draining into the compressor during off-cycles.
If the evaporator were situated below the compressor, the suction riser must be trapped so as to prevent liquid
refrigerant from collecting at the outlet of the evaporator while the system is idle, which would mislead the
expansion valve’s sensor (thermal bulb) at start-up.
Figure 14: Suction lines
Discharge lines
When the condenser is mounted at a higher position than the compressor, a suitably sized “U”-shaped trap close to
the compressor is necessary to prevent oil leaving the compressor from draining back to the discharge side of the
compressor during off cycle. The upper loop also helps avoid condensed liquid refrigerant from draining back to the
compressor when stopped.
Scroll compressors, CH290 and CH485 | Mechanical connections
© Danfoss | Climate Solutions | 2022.09
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