Hitachi RAS-4-HNC - System Installation

3. Piping work and refrigerant charge
70
SMGB0079 rev.0 - 01/2013
3.3.6 System installation
N O T E
• Pipeconnectionsizeonoutdoorunits,indoorunitsandthemultikitordistributorvaryaccordingtothesys-
tem.
• Thesizesoftheindoorandoutdoorunitscouldbedifferent.Adjusttheareadapter(accessory)totheindoor
pipeconnectioninthesecases.

Height Difference Between Indoor Units and Distributor
It is recommended to install all indoor units at the same height. When the height difference between the indoor units due
to building construction is necessary, this should be less than the value indicated in the table. Install the branch pipe at the
same height of indoor units or lower, but never higher.
Indoor unit
Indoor
unit
Height Difference between two
indoors smaller than H
(m)
Smaller than 3
m
Branch pipe
≤
≤
O.U. (HP) H (m)
Premium
2-3 3
4-12 10
Standard 3-12 3

Installing Distributor
1 Install the Distributor supplied by HITACHI on request.
A tee can not be installed instead of a branch pipe.
2 Installing the distributor
Fix the branch pipe horizontally to the pillar, wall or ceiling. Piping must not be xed rigidly to the wall as thermal expansion
and contraction can cause pipe fracture.
Horizontal
To Indoor
Unit
To Outdoor unit
Vertical
To Indoor unit
Fixing the branch pipe to
the surface of pillar or wall
Horizontal
Horizontal
Fixing the branch pipe to
ceiling or beam
N O T E
Fixthepipingfromoutsideofinsulationorinsertingabsorberbetweenthepipeandaxingmetal.