Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 67

[ II Restrictions ]
(2) Line branching
System that requires more than 16 BC controller ports or with multiple BC controllers
<System with both main and sub BC controllers>
Note1) When connecting 2 sub BC controllers to a system, install them in parallel.
Length Total pipe length
Total pipe length from the heat source unit to the
farthest indoor unit
Between heat source unit and BC controller
Between BC controller and indoor unit
Height Between indoor and
difference heat source units
Between indoor unit and BC controller
Between indoor units
Between main BC controller and sub BC controller
Between indoor unit (main BC controller) and
indoor unit (sub BC controller)
*1. When the aggregate length of all pipes exceeds 300m [984ft], observe the restrictions in the figure titled "Restrictions
on pipe length" below.
*2. When the overall pipe length between the BC controller and the farthest indoor unit exceeds 40m [131ft], observe the
restrictions in the figure titled "Restrictions on pipe length" below. (Except the P96 models)
*3. When the capacity of the connected indoor units is P72 or above, use the figures in the parentheses as a reference.
*4. When connecting 2 sub BC controllers to a system, observe the allowable length in the table above.
* A system that requires more than 16 BC controller ports requires two or three BC controllers (main and sub), and
three pipes will be used between the main and the sub BC controllers.
* In the system to which indoor units of P72 model or above are connected, neither a branch joint nor a branch header
may be used.
Restrictions on pipe length
400[1312]
350[1148]
300[984]
250[820]
200[656]
Pipe length between heat source unit and BC controller (m[ft])
Heat source unit
110 m [360ft] or less
A
a
Indoor unit
(P161 - P280 models:
2 ports merged with
a junction pipe)
Junction pipe
(Optional accessory)
Operation
Heat source unit above
indoor unit
Heat source unit below
indoor unit
30 40 50 60 70 80 90 100 110
[98] [131] [164] [196] [229] [262] [295] [328] [360]
<System that requires more than 16 BC controller ports>
Indoor unit Indoor unit
f
BC controller
C
sub unit
Note1)
BC controller
main unit
40 m [131ft] or less
Branch joint
(For use with the Y series)
CMY-Y102S-G
b
B
d
c
Indoor unit
Indoor unit Indoor unit
Maximum of 3 units per port
Total capacity of P160 or below
(All units connected to the same port
must be in the same operating mode)
Indoor unit
Pipe sections
A+B+C
+a+b+c+d+e+f+g
A+C+g or C+g
A
e or C+g
H
H'
h1
h2
h3
h4
The height difference and the pipe length between BC controller and indoor units (A)
70[229]
60[196]
50[164]
40[131]
30[98]
20[65]
10[32]
0
5
[16]
Height difference between main BC controller and farthest indoor unit (m[ft])
- 58 -
g
h3
h4
e
Unit: m [ft]
Allowable length of pipes
*1
300 [984] or less
150 [492] or less
(Equivalent length 175 [574] or less)
110 [360] or less
*2
40 [131] or less
50 [164] or less
40 [131] or less
15 [49] or less (10 [32] or less)
15 [49] or less (10 [32] or less)
15 [49] or less
15 [49] or less (10 [32] or less)
10 15
[32] [49]
*3
*3
*3*4