Multi F Engineering Manual
Design Guideline Summary
Example: LMU540HV outdoor unit with
seven (7) indoor units, and two (2)
branch distribution units connected.
2'82XWGRRU8QLW
,'8,QGRRU8QLW
%'%UDQFK'LVWULEXWLRQ8QLWV
Ȉ$0DLQ3LSH
Ȉ%%UDQFK3LSH%UDQFK'LVWULEXWLRQ8QLW>V@WR
Indoor Unit[s]).
B
A
h2 ≤ 49.2 feet
A
h3 ≤ 32.8 feet
h4 ≤ 49.2 feet
h1 ≤ 98.4 feet
BDU Y-Branch
BDU
IDU
A
ODU
IDU
IDU
IDU
IDU
IDU
IDU
B
B
B
B
B
B
7DEOH Multi F MAX Outdoor Unit Refrigerant Piping System Limitations.
Pipe Length
(ELF = Equivalent
Length of pipe in Feet)
7RWDOSLSLQJOHQJWKȈ$Ȉ%
IHHW
Main pipe (Outdoor Unit to
%UDQFK'LVWULEXWLRQ8QLWVȈ$
Minimum
10 feet
Maximum
IHHW
7RWDOEUDQFKSLSLQJOHQJWKȈ%
IHHW
Branch pipe (Branch Distribu-
WLRQ8QLWVWR,QGRRU8QLWV%
Minimum
10 feet
Maximum
IHHW
Elevation Differential
(All Elevation
Limitations are
Measured in Actual
Feet)
If outdoor unit is above or below indoor unit (h1)
IHHW
Between the farthest two indoor units (h2)
IHHW
Between branch distribution unit and farthest
connected indoor unit(s) (h3)
IHHW
Between branch distribution units (h4)
IHHW
7DEOH Multi F MAX Piping Sizes.
Piping
Main Pipe A
(inch)
Branch Pipe B
Liquid Ø3/8
Depends on the size
of the indoor unit piping
Gas Ø3/4
Example: LMU540HV outdoor unit with
four (4) indoor units, and one (1) branch
distribution unit connected.
2'82XWGRRU8QLW
,'8,QGRRU8QLW
%'8%UDQFK'LVWULEXWLRQ8QLW
$0DLQ3LSH
%%UDQFK3LSH%UDQFK'LVWULEXWLRQ8QLWWR
Indoor Unit[s]).
A
h2 ≤ 49.2 feet
h3 ≤ 32.8 feet
h1 ≤ 98.4 feet
BDU
ODU
IDU
IDU
IDU
IDU
B
B
B
B
Multi F MAX System with One Branch Distribution Unit
Multi F MAX System with Two Branch Distribution Units
7KHIROORZLQJDUHH[DPSOHVRIPDQXDOSLSHVL]HFDOFXODWLRQV'HVLJQHUVDUHKLJKO\HQFRXUDJHGWRXVH/$76IRU0XOWL)V\VWHPV
REFRIGERANT PIPING DESIGN
'XHWRRXUSROLF\RIFRQWLQXRXVSURGXFWLQQRYDWLRQVRPHVSHFL¿FDWLRQVPD\FKDQJHZLWKRXWQRWL¿FDWLRQ
©/*(OHFWURQLFV86$,QF(QJOHZRRG&OLIIV1-$OOULJKWVUHVHUYHG³/*´LVDUHJLVWHUHGWUDGHPDUNRI/*&RUS
200 | DESIGN & PRACTICES
Multi F and Multi F MAX Indoor Unit Engineering Manual
MULTI
F
MAX
MULTI
F