51
Refrigerant Piping System Installation
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MULTI 
F
MAX
MULTI 
F
INSTALLING MULTI F MAX SYSTEMS
Branch 
Distribution 
Unit
Refrigerant Connections 
Pipe Size (in.)
Connectible Indoor Unit Capacity
(Btu/h)
Liquid Vapor
PMBD3620 Ø1/4 x 2 Ø3/8 x 2 7,000, 9,000, 12,000, 15,000, 18,000, 24,000
PMBD3630 Ø1/4 x 3 Ø3/8 x 3 7,000, 9,000, 12,000, 15,000, 18,000, 24,000
PMBD3640 Ø1/4 x 4 Ø3/8 x 4 7,000, 9,000, 12,000, 15,000, 18,000, 24,000
PMBD3641 Ø1/4 x 4
Ø3/8 x 3
7,000, 9,000, 12,000, 15,000, 18,000, 24,000 
(A, B, C) 
Ø1/2 x 1 24,000, 36,000 (D)
Connection sockets (included as a facto-
U\VXSSOLHGDFFHVVRU\ZLWKWKHLQGRRUXQLWV
will need to be used when piping the indoor 
units to the branch distribution unit. The 
connection sockets for 36k indoor units are 
factory supplied with the branch distribution 
units.  See tables above and below for indoor 
unit piping connection and connection socket 
dimensions. See the following page for the 
connection socket installation procedure.
Branch Distribution to Indoor Unit Piping Connections
• Install indoor unit liquid and vapor refrigerant pipes (and connection wiring) to the appro-
priate branch distribution ports. 
• Clearly note on the indoor unit’s refrigerant piping (liquid, vapor) which branch distribution 
port it is connected to (A, B, C, D).
Table 26: Branch Distribution Unit Piping Connections.
Table 27: Indoor Unit Pipe Sizes.
Table 28: Indoor Unit Piping Connections.
Figure 52: Branch Distribution Piping 
Connections. 
ABC D
Indoor Unit 
C a p a c i t y  
Vapor Line
Piping Size (in., OD)
Liquid Line 
Piping Size (in., OD)
7,000 Btu/h
Ø3/8
Ø1/4
9,000 Btu/h
12,000 Btu/h
15,000 Btu/h
15,000 Btu/h: Console; 
18,000 Btu/h
Ø1/2
24,000 Btu/h
36,000 Btu/h Ø5/8 Ø3/8
Table 29: Connection Socket Dimensions.
Indoor  Unit  Capacity                           
Vapor Line
Conn. (in., OD)
Liquid Line
Conn. (in., OD)
7,000 Btu/h
Ø3/8 Ø1/4
9,000 Btu/h
12,000 Btu/h
15,000 Btu/h
18,000 Btu/h: Wall-Mounted Ø5/8 Ø3/8
15,000 Btu/h: Console;
18,000 Btu/h: Low Static Duct, 
Four-Way Cassette, VAHU
Ø1/2 Ø1/4
24,000 Btu/h Ø1/2 Ø1/4
36,000 Btu/h Ø5/8 Ø3/8
Figure 53: Branch Distribution Ports to Indoor 
Units -- Side View. 
Indoor Unit Capacity
Vapor (in., OD) Liquid (in., OD)
A B A B  
18,000 Btu/h: Wall-Mounted ĺĺ ĺ
15,000 Btu/h: Console;
18,000 Btu/h: Low Static Duct, Four-Way 
Cassette, VAHU
ĺ N/A
24,000 Btu/h* ĺ N/A
36,000 Btu/h ĺ ĺ
*No socket adapter is required if connected to Port D on the PMBD3641.
Multi F MAX Outdoor Units
(48, 54, 60 kBtu/h)
(For 7~24 kBtu/h Indoor Units)
(Branch Distribution Unit: PMBD3640)
A
 ROO
M
B ROOM
C ROOM
D ROOM
A ROOM
B ROOM
C ROOM
D ROOM
(Branch Distribution Unit: PMBD3641)
(Ports A~C only for 7~24 kBtu/h
Indoor Units;
Port D only for 24 or 36 kBtu/h
Indoor Units)