LGRED Installation Manual

76
MULTI F / MULTI F MAX with LGRED Outdoor Unit Installation Manual
Due to our policy of continuous product innovation, some specifications may change without notification.
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MULTI
F
MAX
MULTI
F
WITH
Refrigerant Charge
LG Multi F and Multi F MAX with LGRED outdoor units ship from the factory with
a charge of R410A refrigerant. A trim charge may need to be added to take into
account additional piping length.
To determine the additional refrigerant that is needed, apply the formulas below,
and record the results. If the total additional refrigerant charge value is a negative
number, then an additional trim charge does not need to be added to the system.
Additional charge (lbs.) = (Installed Length of Branch [A] – Chargeless Pipe Length [L]) x a
+ (Installed Length of Branch [B] – Chargeless Pipe Length [L]) x a
+ (Installed Length of Branch [C] – Chargeless Pipe Length [L]) x a
+ (Installed Length of Branch [D] – Chargeless Pipe Length [L]) x a
- CF (Correction Factor) x 5.29
Outdoor
Unit Model
Min. to Max. Piping
Length for One
Branch (ft.)
Max. Total System
Piping Length (ft.)
Chargeless Pipe Length
per Branch (L) (ft.)
Piping Length (No Additional
Refrigerant [ft])
Additional Charge
Needed (a) (oz./ft.)
LMU180HHV 9.8 to 82 164 24.6 49.2 0.22
LMU240HHV 9.8 to 82 246.1 24.6 73.8 0.22
LMU300HHV 9.8 to 82 246.1 24.6 98.4 0.22
Outdoor Unit
Factory Charge
oz. of R410A
LMU180HHV 98.8
LMU240HHV 112.8
LMU300HHV 112.8
LMU361HHV 183.4
LMU421HHV 183.4
LMU480HHV 183.4
Table 34: Outdoor Unit Factory Charge.
Multi F with LGRED Systems
• Number of installed length of branches depends on the specifications of the outdoor unit model.
• CF = Maximum number of connectible indoor units – Total number of connected indoor units.
Table 35: 0XOWL)ZLWK/*5('2XWGRRU8QLW3LSLQJ6SHFL¿FDWLRQV
Figure 98: Multi F with LGRED Additional Refrigerant Charge Example.
FINAL INSTALLATION PROCEDURES
Each branch pipe
A = 82 ft.
B = 16 ft.
C = 49 ft.
Additional Charge
A
B
C
9,000
9,000
9,000
Example: LMU300HHV
= (82 - 24.6) x 0.22
+ (16 - 24.6) x 0.22
+ (49 - 24.6) x 0.22
- (4 - 3) x 5.29
= 10.82 oz.