All indoor units are individually connected to ports at the outdoor unit. (As shown below)
• If any refrigerant ports are not connected to indoor units, please tighten the cap to seal off the
port. Paired ports are labeled A, B, C, D, and E.
• During the connection of the indoor unit and the refrigerant pipe, never pull any joints of the
indoor unit by force, otherwise the pipes may crack which would then result in leakage.
• The refrigerant pipe should be supported by brackets, don’t let the unit withstand the weight
of the pipe length. If the piping connection size of the outdoor unit does not match the piping
connection size of the indoor unit, use the piping connection dimension of the indoor unit. Use
a connection joint that will accommodate the transition.
• Each pipe should be labeled to tell which indoor system it belongs to avoid mistaken or
inaccurate piping connections.
Refrigerant Piping Between the Indoor and Outdoor Units
Charging Instructions
M4THM1518A M4THM1524A M4THM1530A M4THM1536A M4THM1542A
ft
m
ft
m
ft
m
ft
m
ft
m
Maximum total length
(a+b+c+d+e)
75
20.5
230
70
230
70
230
70
260
79
Maximum length to any
single indoor unit (Lx)
33
10
65
20
65
20
65
20
80
24
Minimum length to any
single indoor unit
10
3
10
3
10
3
10
3
10
3
Maximum height
difference between
outdoor unit and any
indoor unit *(H1)
20
6
35
10
35
10
50
15
50
15
Maximum height
difference between indoor
units *(H2)
20
6
25
7.5
25
7.5
25
7.5
25
7.5
Maximum total pipe length
before adding charge is
required
66
20
100
30
130
40
130
40
165
50
Minimum total pipe length
before removing charge is
required
33
10
50
15
65
20
80
24
100
30
Amount of R410-A to add
or remove
oz/ft
g/m
oz/ft
g/m
oz/ft
g/m
oz/ft
g/m
oz/ft
g/m
0.22
20
0.22
20
0.22
20
0.24
22
0.24
22
* This height difference limit applies regardless of whether the indoor unit or outdoor unit is higher.
Note: Refer to diagram on page 17.
18
15 Series Multi-Split
Summary of Contents for M4THM1518A
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