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7.4. Allowable pipe length and height difference
See the table below concerning lengths and heights. Refer to figures
8, 9,
12
and 13. Assume that the longest line in the figure
corresponds with the actual longest pipe, and the highest unit in the
figure corresponds with the actual highest unit.
Allowable pipe length
Allowable pipe length
Minimum piping length
All
Maximum total one way piping length
Pair
L1
Twin
L1+L2
Triple
L1+L2
Double twin
L1+L2+L4
Maximum branch piping length
Twin and triple
L2
Double twin
L2+L4
Maximum difference between branch lengths
Twin
L2–L3
Triple
L2–L4
Double twin
L2–L3, L6–L7,
(L2+L4)–(L3+L7)
Maximum height between indoor and outdoor
All
H1
Maximum height between indoors
Twin, triple and
H2
double twin
Chargeless length
All
L1+L2+L3+L4+L5
+L6+L7
(1) The minimum piping length must be 5 m. If installation is performed with less field
piping, the system will be overcharged (abnormal HP, etc.). If the distance
between indoor and outdoor unit is less than 5 m, please make sure that the
piping length is ≥5 m by additional bending of the pipes.
If size-up of liquid pipes are used, the indoor
unit must be installed on a lower location than
the outdoor unit.
7.5. Existing or pre-installed piping can be used
1.
Piping must comply with the criteria below.
•
Pipe diameter must comply with the limitations as indicated in
paragraph
"7.2. Refrigerant pipe size" on page
•
Piping length must be within limits of the allowable piping length
as in paragraph
"7.4. Allowable pipe length and height difference"
on page
5.
•
Piping
must
be
designed
"7.1. Selection of piping material" on page
2.
Only main piping can be reused without cleaning when:
•
Total 1-way piping length: <50 m.
•
No compressor breakdown has occured in the history of the unit
to be replaced.
•
A correct pump down operation can be executed:
-
Operate the unit continuously for 30 minutes in cooling
mode.
-
Execute a pump down operation.
-
Remove the airconditioning units to be replaced.
•
Check the contamination inside the existing piping.
If you cannot meet all these requirements, the existing pipes must be
cleaned or replaced after removing the air conditioning units to be
replaced.
3.
Prepare the flare connections for higher pressure. See paragraph
"FLARE SHAPE and FLARENUT TIGHTENING TORQUE" on
page
6.
Installation manual
5
(1)
5 m
standard
100 m
size-up of gas pipe
100 m
size-up of liquid pipe
50 m
—
100 m
—
100 m
—
100 m
—
20 m
—
20 m
—
10 m
—
10 m
—
10 m
—
30 m
—
0.5 m
standard
30 m
size-up of gas pipe
30 m
size-up of liquid pipe
10 m
4.
for
R410A.
See
paragraph
4.
7.6. Precautions on refrigerant piping
Do not allow anything other than the designated refrigerant to
get mixed into the freezing cycle, such as air, etc. If any
refrigerant gas leaks while working on the unit, ventilate the
room thoroughly right away.
In order to prevent dirt, liquid or dust from entering the piping,
cure the piping with a pinch or taping.
Place
Installation period
More than a month
Outdoor side
Less than a month
Indoor side
Regardless of the period
Great caution is needed when passing copper tubes through
walls.
In case of simultaneous operating system
-
Upward and downward piping should be performed at the
main piping line.
-
Use branch piping kit (optional) for branching refrigerant
pipes.
Precautions to be taken. (For details, refer to the manual attached to
branch piping kit.)
-
Install the branch pipes horizontally (with a maximum
inclination of 15°) or vertically.
-
Length of branch pipe to the indoor unit should be as short as
possible.
-
Try to keep lengths of both branch pipes to the indoor unit
equal.
When re-using existing refrigerant piping
Pay attention to the following points when re-using existing
refrigerant piping
Perform a visual check on quality of residual oil in existing
refrigerant piping.
This check is extremely important because using existing
piping
with
deteriorated
breakdown.
- Put some residual oil of the pipes you want to reuse on a
piece of white paper or on the white surface of an oil
checking reference card and compare that oil color with the
circled color of the oil checking reference card.
- If oil color is identical to the circled color or darker, replace
the piping, install new piping or clean the piping thoroughly.
- If oil color is lighter, the pipes can be reused without
cleaning.
An oil checking reference card is indispensable for such
evaluation and can be obtained at your dealer.
In the following situations, the existing piping should not be
re-used and new piping should be installed.
- If the previously used model had problems with its
compressor (this might cause oxidized coolant oil, scale
residue and other adverse effects).
- If the indoor or outdoor units were disconnected from the
piping for a long period of time (water or dirt might have
gotten into the piping).
- If copper piping is corroded.
Existing flares may not be re-used but new ones must be
made in order to prevent leaks.
Check welded connections for gas leaks, if the local piping
has welded connections.
Replace deteriorated insulation with new material.
Protection method
Pinch the pipe
Pinch or tape the pipe
oil
will
cause
compressor
RZQ200+250B8W1B
Split system air conditioner
4PW25544-1A
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