LG Multi V 5 - Self-Diagnosis Function

074
_TROUBLE SHOOTING GUIDE BOOK
5.2.1 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 EEV
: EEV pulse ↑ for decreasing sub-cooling
* in some cases, mal-distribution of ref. among indoor units causes lack of ref. supply to specific
IDUs, thus EEV pulse can be increased regardless of ref. conditions
* In case of refrigerant shortage, cycle will show opposite response.
5.2 Heating 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  Increasing liquid area (SC ↑)
 Performance ↓  High Pressure ↑
• ODU EEV
: EEV pulse ↑ for decreasing sub-cooling
* in
some cases, mal-distribution of ref. among indoor units causes lack of ref. supply to
specific IDUs, thus EEV pulse can be increased regardless of ref. conditions
5.2.1 A cycle changes by refrigerant overcharging
comp
liquid
2-phase
superheat
2-phase
ODU HEX
IDU HEX
Outdoor unit Fan
IDU EEV
ODU Main EEV
SC EEV
Indoor unit Fan
[Comp. Hz]
IDU Hex performance↓(by
reduced 2 phase region) 
High Pressure ↑  Comp Hz ↓
(target High Pressure control)
[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)]
Sub cooled liquid area↑ 
 density of refrigerant ↑
 SC EEV ↓
[ODU EEV]
SC↑  Density of refrigerant ↑
 ODU Main EEV ↓
[Suction SH]
Main EEV is controlled for SH = 2~5℃
So, Suction SH ↓ and Main EEV ↓
20170217 Trouble Shooting Guide Book_Multi5_신규추가
* In case of refrigerant shortage, cycle will show opposite response.
5.2 Heating cycle
Self-Diagnosis Function
1. Error Code Display 076
2. Error Code Check 080
Ⅲ. Trouble Shooting Guide
Basic Part
Multi V 5
Intorduction
Trouble Shooting
Function Control
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