Multi F Engineering Manual

Example: LMU541HV outdoor unit with
seven (7) indoor units, and two (2)
branch distribution units connected.
ODU: Outdoor Unit.
IDU: Indoor Unit.
BD: Branch Distribution Unit(s).
A: Main Pipe.
B: Branch Pipe (Branch Distribution Unit[s] to
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
Table 37: Multi F MAX Outdoor Unit Refrigerant Piping System Limitations.
Table 38: 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: LMU541HV outdoor unit with
four (4) indoor units, and one (1) branch
distribution unit connected.
ODU: Outdoor Unit.
IDU: Indoor Unit.
BDU: Branch Distribution Unit.
A: Main Pipe.
B: Branch Pipe (Branch Distribution Unit to
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
Example of a Multi F MAX System with One Branch Distribution Unit
Example of a Multi F MAX System with Two Branch Distribution Units
PIPING LIMITATIONS
Following pages present Multi F / MAX piping limitations and are for illustrative purposes only. Designers are highly encouraged to use LATS when
designing Multi F / MAX systems.
Pipe Length
(ELF = Equivalent
Length of pipe in Feet)
7RWDO SLSLQJ OHQJWK Ȉ$  Ȉ%
 IHHW
Main pipe (Outdoor Unit to
Branch Distribution Units: A)
Minimum for Each
(A) Piping Segment
16.4 feet
0D[LPXP Ȉ$
 IHHW
7RWDO EUDQFK SLSLQJ OHQJWK Ȉ%
 IHHW
Branch pipe (Branch Distribu-
tion Units to Indoor Units: B)
Minimum
16.4 feet
Maximum
 IHHW
Elevation Differential
(All Elevation
Limitations are
Measured in Actual
Feet)
If outdoor unit is above or below indoor unit (h1)
 IHHW
Between the farthest two indoor units (h2)
 IHHW
Between branch distribution unit and farthest
connected indoor unit(s) (h3)
 IHHW
Between branch distribution units (h4)
 IHHW
'XHWRRXUSROLF\RIFRQWLQXRXVSURGXFWLQQRYDWLRQVRPHVSHFL¿FDWLRQVPD\FKDQJHZLWKRXWQRWL¿FDWLRQ
©/*(OHFWURQLFV86$,QF(QJOHZRRG&OLIIV1-$OOULJKWVUHVHUYHG³/*´LVDUHJLVWHUHGWUDGHPDUNRI/*&RUS
66 | PIPING AND PLACEMENT
Multi F and Multi F MAX Heat Pump System Engineering Manual
MULTI
F
MAX
MULTI
F