Hitachi UTOPIA RASC Series Installation And Operation Manual page 32

REFRIGERANT PIPING &
REFRIGERANT CHARGE
11.4.3.TWIN AND QUAD SYSTEM INSTALLATION
Height Difference Between Indoor Units and Distributor
•
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 0,5
meters. Install the branch pipe at the same height of indoor
units or lower, but never higher.
Sample: Twin system
Height difference between two
indoors. Smaller than 0.5m
Indoor units
Smaller than
0.5 mm
Piping size for Indoor Unit.
•
The piping size for indoor unit are as follows
Unit
1.5 HP
2.0 HP
2.5 HP
Installing Distributor
•
1. Install the Distributor supplied by HITACHI on request
A tee can not be installed instead of a branch pipe.
Sample: Twin System
2. Installing the Distributor.
Fix the branch pipe horizontally to the pillar, wall or ceiling.
Piping must not be fixed rigidly to the wall as thermal
expansion and contraction can cause pipe fracture.
Sample: Twin System
Horizontal
To indoor unit
Fixing the branch pipie to
To RASC unit
the surface of pillar or wall

NOTE:
- Fix the piping from outside of insulation or inserting
absorber between the pipe and a fixing metal.
Branch pipe
Gas piping size Liquid piping size
12.7 (1/2")
6.35 (1/4")
15.88 (5/8")
9.53 (3/8")
To indoor unit Horizontal
Fixing the branch pipe to
ceiling or beam
3. Correct position of twin distributor
This is the correct position of twin Branch Pipe:
•
Greater
than 0.5m
This is wrong position.
•
Branch pipe
mm(in.)
4. Correct position of Quad Distributor.
Install the header horizontally
•
Sample: Quad Branch pipe
Gas piping
Liquid piping
Horizontal
Up
Refrigerant
Main Pipe
direction
Main Pipe
Branch pipe
Refrigerant direction
Down
Up
Main Pipe
Main Pipe
Refrigerant
direction
Branch pipe Branch pipe
Down
PMML0140A rev.1 - 07/2009
32