Cautions For Installation - Toshiba SMMS-e Quick Reference

Refrigerant Piping
6

Cautions for installation

• Set the outdoor unit first connected to the bridging pipe to the indoor units as the header unit.
• Install the outdoor units in order of their capacity codes: A (header unit)
• When connecting gas pipes to indoor units, use Y-shaped branching joints to keep pipes level.
• When piping to outdoor units using Outdoor unit connection piping kits, intersect the pipes to the outdoor unit and
those to indoor units at a right angle as shown in figure 1 on "Installation of the outdoor unit". Do not connect
them as in figure 2 on "Installation of the outdoor unit".
Liquid piping
Allowable length and allowable height difference of refrigerant piping
Total extension of pipe (Liquid
pipe, real length)
Farthest piping Length L (*1)
Equivalent length of farthest piping from 1st
branching Li (*1)
Piping length Equivalent length of farthest piping between
outdoor units LO
Max. equivalent length of main
piping
Max. equivalent length of outdoor unit connecting
piping
Max. real length of indoor unit connecting piping
Max. equivalent length between branches
Height between indoor and
outdoor units H1
Difference in
height
H e g i t h
H e g i t h
(*1) : (C) is outdoor unit furthest from the 1st branch and (j) is the indoor unit furthest from the 1st branch.
(*2) : If the height difference (H1) between indoor and outdoor unit exceeds 3m, set 65m or less.
(*3) : If the max. combined outdoor unit capacity is 46HP or more, then max. equivalent length is 70m or less
(real length is 50m or less).
(*4) : If the height difference (H2) between indoor units exceeds 3m, set 50m or less.
(*5) : If the height difference (H2) between indoor units exceeds 3m, set 30m or less.
(*6) : Total charging refrigerant is 140kg or less.
(*7) : Extension up till 90m is possible with conditions below.
- Outdoor Temperature Cooling : 10°C to 46°C (Dry-bulb temp.)
Heating : -5°C to 15.5°C (Wet-bulb temp.)
- Equivalent length of farthest piping from 1st branching Li<50m
- Real length of main piping L1<100m
- Height difference between indoor units H2<3m
- Total capacity of combined indoor units : 90%-105%
- Single CDU, and up to 20HP
- Minimum capacity of connectable indoor unit : 4HP or Larger
Correct
▼ Figure 1
Header unit Follower unit
A B
Main pipe
To the indoor unit
Item
b e w t e e n n i d o r o u n s t i H 2
b e w t e e n o u d t o r o u n s t i H 3
<Cooling,Heat pump type>
Incorrect
Follower unit Header unit
C A
NO GOOD
Main pipe
To the indoor unit
Allowable
value
Below 34HP 300m
34HP or more 1000m (*6)
Equivalent
235m
length
Real length 190m
90m (*2)
25m
Equivalent
120m (*3)
length
Real length 100m (*3)
10m
30m
50m
70m
Upper outdoor
(*4, *7)
unit
Lower outdoor
4 0 m * ( ) 5
unit
4 0 m
5 m
B C
▼ Figure 2
Follower unit Follower unit
B C
Piping section
LA + LB + La + Lb + Lc+ L1 + L2 + L3 +
L4+ L5 +L6 + L7 + a + b + c + d + e + f +
g + h + i + j
LA+ L1 + L3 + L4 + L5 + L6 + j
L3 + L4 + L5 + L6 + j
LA + Lc(LA + Lb)
L1
Lc(La, Lb)
a, b, c, d, e, f, g, h, i, j
L2, L3, L4, L5, L6, L7
–
–
–
–