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11.4.2. TWIN, TRIPLE 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 H
height of indoor units or lower, but never higher.
Sample: Twin system
Indoor unit
Height Difference between two
Indoor unit
indoors smaller than H
Smaller than H
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
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 (available also for quad installation)
- This is the correct position of twin Branch Pipe:
Greater
than 0.5 m
Main pipe
Refrigerant direction
- This is wrong position.
Refrigerant direction
Main pipe
Branch pipe
Branch pipe
PMML0197_r0_04-10.indb 29
INSTALLATION AND OPERATION MANUAL
(m). Install the branch pipe at the same
in
Branch pipe
(m)
in
Maximum Height
(m)
difference between
in
H
Indoor units
H(V)RNM(1)E
3.0
HVRNS1E
0.5
To Indoor unit
Horizontal
Horizontal
Fixing the branch pipe to
ceiling or beam
Up
Branch pipe
Refrigerant
direction
Main pipe
Down
Branch pipe
Refrigerant
direction
Main pipe
4. Correct position of Triple Branch Pipe.
-
Install the header horizontally
Sample: Triple Branch pipe
Gas piping
Liquid piping
11.4.3. BRAZING WORK
in
ATTENTION:
Use nitrogen gas for blowing during pipe brazing. If oxygen,
acetylene or fluorocarbon gas is used, it will cause an explosion or
poisonous gas.
A lot of oxidation film will occur inside of tubes if no nitrogen gas
blowing is performed during brazing work. This film will be flecked
off after operation and will circulate in the cycle, resulting in
clogged expansion valves, etc. This will cause bad influence to the
compressor.
Use a reducer valve when nitrogen gas blowing is performed
during brazing. The gas pressure should be maintained within 0.03
to 0.05 Mpa. If a excessively high pressure is applied to a pipe, it
will cause an explosion.
11.4.4. REFRIGERANT CHARGE
CAUTION:
Do not charge OXYGEN, ACETYLENE, or other flammable and
poisonous gases into the refrigerant because an explosion can
occur. It is recommended that oxygen free nitrogen be charged for
these types of tests cycle when performing a leakage test or an
airtight test. These types of gases are extremely dangerous,
Insulate the unions and flare-nuts at the piping connection part
completely.
Insulate the liquid piping completely to avoid a decrease of
performance; if not, it will cause sweating on the surface of the
pipe.
Charge refrigerant correctly. Overcharging or insufficient charging
could cause a compressor failure.
Check for refrigerant leakage in detail. If a large refrigerant
leakage occurred, it would cause difficulty with breathing or
harmful gases would occur if a fire were being used in the room.
If the flare nut is tigthened too hard, the flare nut may crack after a
long time and cause refrigerant leakage.
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08/07/2010 9:20:46
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