Hitachi HRNM Série Manuel D'installation page 37

12.2.1. REFRIGERANT PIPING SELECTION
Select the piping connection sizes according to the following
procedures:
Between Outdoor Unit and branch pipe:
Select the same pipe connection size as the pipe size
of the Outdoor Unit
Between branch pipe and Indoor Unit:
Select the same pipe connection size as the pipe size
of the Indoor Unit
Piping connection size of Outdoor Unit, Indoor Unit &
Distributor
Pipe Size
Outdoor
Liquid
Unit
Gas Pipe
Pipe
RAS-8 HP 9.53 (3/8")* 25.4 (1")
RAS-10 HP 12.7 (1/2") 25.4 (1")
RAS-12 HP 12.7 (1/2") 25.4 (1")
(*) Select the piping size of the Ø12.7 (1/2") when the length is more than
70m (Only RAS-8)
Pipe Connection size between units
Gas piping Size
Indoor Unit
(B, C, D or E)
2.0HP 15.88 (5/8")
2.5~6.0HP 15.88 (5/8")
8.0HP* 22,2 (7/8")
10.0HP* 9.05 (3/4")
(*) Dimensions after reducction pipe.
12.2.2. TWIN AND TRIPLE 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 3 meters. Install the branch pipe at the same
height of indoor units or lower, but never higher.
Sample: Twin system
Indoor Unit
Height Difference Between
Indoor Unit
Two Indoors. Smaller than
3m
Smaller than 3m
Installing Distributor
1. Install the Distributor supplied by HITACHI on request
the T-Joint can not be installed instead of a branch pipe.
Sample: Twin System
Branch Pipe
Twin Triple Quad
TE-08N TRE-810N QE-810N
TE-10N TRE-810N QE-810N
TE-10N TRE-810N QE-810N
Liquid piping Size
(B, C, D or E)
6.35 (1/4")
9.53 (3/8")
9.53 (3/8")
9.53 (3/8")
Branch Pipe
PIPING AND REFRIGERANT CHARGE
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
To Indoor Unit
Horizontal
To Indoor
Vertical
Unit
To Outdoor Unit Fixing the Branch Pipe to
the surface of Pillar or Wall
NOTE:
Fix the piping from outside of insulation or inserting
absorber between the pipe and a fixing metal.
3. Correct position of twin distributor
This is the correct position of twin Branch Pipe:
Up
Greater
Main Pipe
than 0,5 m
Down
Refrigerant direction
This is wrong position.
Refrigerant direction
Main Pipe
Branch Pipe
Branch Pipe
4. Correct position of Triple Branch Pipe.
Install the header horizontally
Sample: Triple Branch pipe
Gas piping
Liquid piping
Horizontal
Horizontal
Fixing the Branch
Pipe to Ceiling or
Beam
Branch Pipe
Refrigerant
direction
Main Pipe
Up
Main Pipe
Refrigerant
direction
Branch Pipe
Down
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