18
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Piping installation
Installer and user reference guide
89
REMA5+REYA8~20A7Y1B
VRV 5 heat recovery
4P687640-1 – 2022.07
Pipe
Maximum length (actual/equivalent)
Longest pipe from the outdoor unit or
the last multi-outdoor piping branch (A
+B1+C1, A+B2+C2, A+B1+C3, A+B1+D
+C4)
135 m/160 m
(a)
Longest pipe after the first branch or
multi BS unit (B1+C1, B2+C2, B1+C3,
B1+D+C4)
40 m/—
(b)
In case of a multi-outdoor setup:
longest pipe from the outdoor unit to
the last multi-outdoor piping branch (E)
10 m/13 m
Total pipe length
500 m/—
(a)
If the equivalent piping length is more than 90 m, size up the main liquid piping according
to
"18.1.4 To select the piping size"
(b)
The limitation can be extended to 90 m if the following conditions are met:
•
The piping length between all indoor units and the BS unit is ≤40 m.
•
Size-up:
→ It is required to size-up the liquid piping between the first branch kit or BS unit and the last
branch kit or last BS unit.
→ It is also required to size-up the liquid piping downstream of the BS unit if the last refrigerant
branch kit is located downstream of the BS unit.
→ It is not required to size-up the liquid piping between the BS unit and indoor units.
→ If the increased pipe size is larger than the pipe size of the main pipe, also increase the size of the
main pipe.
•
In case of size-up of the liquid piping, double its length in the calculation of the total piping length.
Make sure the total piping length is within limitations.
•
The piping length difference between the nearest indoor unit to the outdoor unit and the farthest
indoor unit to the outdoor unit is ≤40 m.
18.1.10 Multiple outdoor units: Possible layouts
▪
The piping between the outdoor units must be routed level or slightly upward to
avoid the risk of oil retention into the piping.
Pattern 1
a
b
b
a
Pattern 2
b
a
a
b
a
b
b
a
a
To indoor unit
b
Piping between outdoor units
NOT allowed (oil remains in piping)
Allowed
▪
To avoid the risk of oil retention to the outmost outdoor unit, always connect the
stop valve and the piping between outdoor units as shown in the correct ( )
possibilities of the figure below.
