LG Multi V 5 - Cycle Changes by Amount of Refrigerant

072 073
_TROUBLE SHOOTING GUIDE BOOK _
5.1 Cooling cycle
5. Cycle Changes by amount of refrigerant
5.1.1 A cycle changes by refrigerant overcharging
When overcharging a refrigerant more than necessary, an extra refrigerant will be stored in con-
densing HEX and liquid pipe because of high density. Overcharged refrigerant can make changing
the cycle as below.
To make clear distinction, all IDU's should be operated, and wait at least 20 minutes after system
started until cycle is stabilized
• ODU HEX
: Accumulation of refrigerant in condensing area → Increasing liquid area (SC ↑)
→ Performance ↓ → High Pressure ↑
• ODU Fan
: RPM ↑ to reduce high pressure
* In case of refrigerant shortage, cycle will show opposite response.
5. Cycle Changes by amount of refrigerant
5.1 Cooling cycle
When overcharging a refrigerant more than necessary, an extra refrigerant will be
stored in condensing HEX and liquid pipe because of high density. Overcharged
refrigerant can make changing the cycle as below.
To make clear distinction, all IDU’s should be operated, and wait at least 20 minutes
after system started until cycle is stabilized
• ODU HEX
: Accumulation of refrigerant in condensing area  liquid area increase (SC ↑)
 Performance ↓  High Pressure ↑
• ODU Fan
: RPM ↑ to reduce high pressure
5.1.1 A cycle changes by refrigerant overcharging
comp
liquid
2-phase
superheat
2-phase
Indoor unit HEX
ODU HEX
Indoor unit Fan
ODU Main EEV
IDU EEV
SC EEV
Outdoor Unit Fan
[Comp. Hz]
Base pressure ↑(OFF condition
pressure)  Difference
between target low pressure
and base pressure ↑ Comp
Hz ↑
[Discharge Super heat(SH)]
Density of refrigerant for suction ↑
 Circulating more refrigerant
than same Hz  Comp. cooling
effect ↑  Discharge SH↓
[SC EEV, Sub cooling(SC)]
Liquid area↑  SC↑
 Density of refrigerant ↑
 SC EEV ↓
[IDU EEV]
SC↑  Density of refrigerant ↑
 IDU EEV ↓
[Indoor SH]
EEV is controlled for SH=0~5℃ until 110pulse
20170217 Trouble Shooting Guide Book_Multi5_신규추가
* In case of refrigerant shortage, cycle will show opposite response.
4.4 Abnormal cycle (Refrigerant Overcharging / Shortage)
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