Toshiba MMU-AP0072H2UL Engineering Data Book page 26

3
Refrigerant piping design
3-2-2. Heat pump
Height
difference
between
Header unit (A)
outdoor
units
H3 ≤ 16 ft
(5 m)
(a)
La
Height
difference
between
outdoor
and indoor
units:
H1 ≤ 230 ft
(70 m)
First branching
section
System restrictions
Max. No. of combined outdoor units
Max. capacity of combined outdoor units
Max. No. of connected indoor units
Max. capacity of combined indoor units
Allowable length and height difference of refrigerant piping
Total extension of pipe (liquid pipe)
Farthest piping length L (*1)
Main piping length
Pipe length
Farthest equivalent piping length from the first
branch Li (*2)
Maximum equivalent piping length of pipes connected to outdoor units
Maximum actual length of pipes connected to indoor units
Maximum equivalent length between branching sections
Height between outdoor and
indoor units H1
Height difference
Height between indoor units H2
Height between outdoor units H3
*1: If "Medium Static Ducted Type (MMD-AP***BH)" is included in the system: Total indoor capacity code is between 80% and 120% of the capacity of the outdoor unit.
*2: Farthest outdoor unit from the first branch: (B), farthest indoor unit: (j).
Follower unit (B)
(b)
Lb
Branching pipe L2 Branching header
Indoor unit
connecting
pipe
a b
L3
The longest piping length: L ≤ 720 ft (220 m)
The longest piping length from the first branch: Li ≤ 295 ft (90 m)
L5
Y-joint L4
f g
Indoor unit
2 units
19 ton
38 units
H2 ≤ 49 ft (15 m) 125% (*1)
H2 > 49 ft (15 m) 105%
Item
Actual length
Equivalent length
Actual length
Equivalent length
Actual length
H1 > 9.8 ft (3 m)
H1 ≤ 9.8 ft (3 m)
H2 > 9.8 ft (3 m)
Upper outdoor units
H2 ≤ 9.8 ft (3 m)
H2 > 9.8 ft (3 m)
Lower outdoor units
H2 ≤ 9.8 ft (3 m)
Liquid piping
Figure 1
Correct
Header unit Follower unit
A B
Main pipe
To the indoor unit
Gas piping
Figure 3
Correct
Header unit Follower unit
A B
Main pipe
To the indoor unit
L7
c d e
L6
h i
j
(j)
Note 1) The header unit is connected to main piping to indoor units.
Note 2) The header unit is the one with the highest capacity code. A (header unit) ≥ B
Note 3) To connect suction gas pipes to indoor units, use Y-shaped branching joints to
keep pipes level.
Allowable value (ft (m))
985 (300)
720 (220)
590 (180)
395 (120)
330 (100)
215 (65)
295 (90)
33 (10)
98 (30)
165 (50)
165 (50)
230 (70)
98 (30)
130 (40)
130 (40)
16 (5)
25
Figure 2
Incorrect
Header unit Follower unit
A B
Incorrect
Main pipe
To the indoor unit
[Inverse connection of a gas-side branch unit]
Figure 4
Incorrect
Header unit Follower unit
A B
Main pipe
To the indoor unit
To gas-side branch unit
Height
difference
between
indoor units:
H2 ≤ 130 ft
(40 m)
Pipes
La + Lb + L1 + L2 + L3 + L4 + L5 + L6 + L7 + a + b + c + d +
e + f + g + h + i + j
Lb + L1 + L3 + L4 + L5 + L6 + j
L1
L3 + L4 + L5 + L6 + j
La, Lb
a, b, c, d, e, f, g, h, i, j
L2, L3, L4, L5, L6, L7
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