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6. REFRIGERANT PIPING WORK
• For instruction for installing piping between the outdoor unit and BS unit, selecting a refrigerant branch kit,
and installing piping between the refrigerant branch kit and the indoor unit, refer to the installation manual
and equipment design materials included with the outdoor unit.
• Before beginning the work, always check to make sure the type of refrigerant used is R410A. (The unit will
not operate correctly with a different type of refrigerant.)
• Insulate all of the piping including the liquid pipes, HP/LP gas pipes, suction gas pipes, gas pipes, equalizer
pipes (piping between outdoor units when an outdoor multi-unit system), and the pipe connections for
these. Not insulting these pipes could result in water leaks or burns. In particular, suction gas flows in the
HP/LP gas piping during full cooling operation, so the same amount of insulation as used for the suction
gas piping is required. In addition, high-pressure gas flows in the HP/LP gas piping and gas piping, so use
insulation that can withstand more than 120˚C.
• Reinforce the insulation material when necessary for the installation environment. Refer to the following as
a guideline.
• For 30˚C, RH75% to 80%: Thickness at least 15mm
• For 30˚C, over RH80%: Thickness at least 20mm
If not reinforced, condensation could form on the surface of the insulation. For details, refer to the
Engineering data book.
NOTES
• This product only uses the new refrigerant (R410A). Be sure to use the special pipe cutters for R410A,
during installation.
• Make sure that nothing besides the specified refrigerant, such as air, gets into the refrigerant piping.
• If refrigerant gas leaks during the work, ventilate the area. (The outdoor units are filled with refrigerant.)
6-1 PIPING MATERIAL SELECTION
• Use only pipes which are clean inside and outside and which do not accumulate harmful sulfur, oxidants,
dirt, cutting oils, moisture, or other contamination. (Foreign materials inside pipes including oils for
fabrication must be 30mg/10m or less.)
• Use the following items for the refrigerant piping.
Material: Jointless phosphor-deoxidized copper pipe
Size: See "Example of connection" to determine the correct size.
Thickness: Select a thickness for the refrigerant piping which complies with national and local laws.
For R410A, the design pressure is 4.0 MPa (40bar).
The minimum thickness and temper grade (O type, 1/2H type) of piping is shown below.
Temper grade
outer diameter
smallest thickness
Temper grade
outer diameter
smallest thickness
• For information regarding the piping allowable maximum length, allowable height difference, and allowable
length after a branch, refer to the installation manual that came with the outdoor unit or Engineering data
book.
• The refrigerant branch kit (sold separately) is required for piping branches. For information on how to select
a refrigerant branch kit, refer to the Installation Manual that came with the outdoor unit or Engineering data
book.
English
O type
φ6.4
φ9.5
φ12.7
0.80
0.80
0.80
φ19.1
φ22.2
φ25.4
0.80
0.80
0.88
(unit: mm)
φ15.9
0.99
1/2H type
φ28.6
φ31.8
φ34.9
0.99
1.10
1.21
(unit: mm)
φ38.1
φ41.3
1.32
1.43
8
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