Self-Diagnosis Function - LG MULTI V 5 Manual Book

20170217 Trouble Shooting Guide Book_Multi5_신규추가
5.2 Heating cycle
5.2.1 A cycle changes by refrigerant overcharging
5.2 Heating cycle
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
5.2.1 A cycle changes by refrigerant overcharging
the cycle as below.
To make clear distinction, all IDU's should be operated, and wait at least 20 minutes after system
When overcharging a refrigerant more than necessary, an extra refrigerant will be
stored in condensing HEX and liquid pipe because of high density. Overcharged
started until cycle is stabilized
refrigerant can make changing the cycle as below.
To make clear distinction, all IDU's should be operated, and wait at least 20 minutes
• ODU HEX
after system started until cycle is stabilized
: Accumulation of refrigerant in condensing area → Increasing liquid area (SC ↑)
• ODU HEX
→ Performance ↓ → High Pressure ↑
: Accumulation of refrigerant in condensing area  Increasing liquid area (SC ↑)
• ODU EEV
 Performance ↓  High Pressure ↑
: EEV pulse ↑ for decreasing sub-cooling
• ODU EEV
* in some cases, mal-distribution of ref. among indoor units causes lack of ref. supply to specific
: EEV pulse ↑ for decreasing sub-cooling
IDUs, thus EEV pulse can be increased regardless of ref. conditions
* 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
Indoor unit Fan
IDU EEV
liquid
2-phase
[SC EEV, Sub cooling(SC)]
SC EEV 2-phase
Sub cooled liquid area↑ 
 density of refrigerant ↑
 SC EEV ↓
ODU Main EEV
ODU HEX
[ODU EEV]
SC↑  Density of refrigerant ↑
 ODU Main EEV ↓
Outdoor unit Fan
* In case of refrigerant shortage, cycle will show opposite response.
* In case of refrigerant shortage, cycle will show opposite response.
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_TROUBLE SHOOTING GUIDE BOOK
[Discharge Super heat(SH)]
Density of refrigerant for suction ↑
IDU HEX  Circulating more refrigerant
than same Hz  Comp. cooling
effect ↑  Discharge SH↓
superheat
comp
[Comp. Hz]
IDU Hex performance↓(by
reduced 2 phase region) 
High Pressure ↑  Comp Hz ↓
(target High Pressure control)
[Suction SH]
Main EEV is controlled for SH = 2~5℃
So, Suction SH ↓ and Main EEV ↓
Ⅲ. Trouble Shooting Guide

Self-Diagnosis Function

1. Error Code Display
2. Error Code Check
076
080