Hitachi HRNM Série Manuel D'installation page 36

PIPING AND REFRIGERANT CHARGE
24
12.2. REFRIGERANT PIPING LENGTH
The refrigerant piping between the indoor unit and the outdoor unit should be designed using the following chart.
Keep the design point within the dark area of the chart, which is showing the applicable height difference according to piping
length.
In case that a piping length is shorter than 5 meters, contact the Hitachi dealer.
Piping Length specification:
RAS-8~12
When the
Outdoor unit is Height Total length between
installed difference Outdoor Unit and each
heigher than
(m)
Indoor Unit
When the
Outdoor unit is
installed lower
than Indoor
Unit
The possible combination between Outdoor Unit and Indoor Unit are the following:
Single System
Quad System
L= A + Longest of B, C, D & E
NOTE:
L&H are the Length & Height indicated in the above
chart.
For twin, triple and quad the length is the distance
between the Outdoor Unit and the farther Indoor Unit
Indoor Unit L(m)
Twin System
L= A + Longest of B & C L= A + Longest of B, C & D
Distance must be bigger than
Mark Maximum Piping Length
Actual piping length
L
Equivalent piping length
Outdoor unit higher than indoor unit
H
Indoor unit higher than outdoor unit
Piping length after branch pipe (B,C,D & E):
1. After branch pipe B,C & D, the pipe length should be
shorter than 15 m.
2. All branch pipe, B, C, D & E (it depend of case), should
be balanced, the difference between them cannot be
bigger than indicated in the table bellow:
Twin B & C difference
Triple B, C & D difference
B, C, D & E difference
Quad
Triple System
B+C+D
100m
125m
30m
20m
8m