Selection Of Branch Pipe; Allowable Pipe Length And Height Difference; Existing Or Pre-Installed Piping Can Be Used; Precautions On Refrigerant Piping - Daikin RZQ200C7Y1B Installation Manual

7.3. Selection of branch pipe

Twin KHRQ22M20TA
Triple KHRQ250H
Double twin KHRQ22M20TA (3x)

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
difference" on page 5.
• Piping must be designed for R410A. See paragraph
"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.
RZQ200+250C7Y1B
Split system air conditioner
4PW34720-1G – 07.2010
(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.
"7.4. Allowable pipe length and height
4.
• 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.

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
Installation manual
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