Daikin VRV II Series, Design, Installation & Testing Instructions, Page: 27 / 242

Si39-303 Installation
General Information 21
(The nature and amount of the extraneous material inside the pipe can be checked during flushing by
placing a rag lightly over the end of the pipe. In the unlikely case that even a small quantity of moisture is
found then the inside of the pipe should be dried out thoroughly.)
Action:
1. Flush the inside of the pipe with nitrogen gas. (Until such time as the moisture disappears.)
2. Carry out a thorough vacuum drying operation. (See page 31)
Close the main valve on the nitrogen cylinder.
Repeat the above operation for unit B.
When the liquid pipe operations have been completed then do the same with the gas pipes.
Choice of
Materials for
Refrigerant
Piping
a) Refrigerant piping
!
The piping used must meet the requirements of the JIS standard or equivalent. (Size, material,
thickness, etc.)
Specification:
Oxidized phosphorous seamless copper pipe
!
Long pipe lengths or coiled pipe (copper pipe with heat insulation coating) should be used to avoid the
necessity for frequent brazing.
(* Make sure the thickness and material shall be selected in accordance with following table.)
!
Size of Refrigerant Piping
*The thickness and material shall be selected in accordance with local code.
b) Brazed joints and special branches
1. General use (L bend joint, socket joint, T joint, etc.)
!
Joints must meet the requirements of the relevant JIS standard. (Size, materials, thickness, etc.)
2. Special branches
!
The Daikin outdoor unit multi connection kit, REFNET joint, REFNET header or Reducing socket should
be used.
Example: R410A RXYQ-M Series
Refer detail of DAIKIN REFNET joint and REFNET header on page 126.
Outside Diameter (mm) Material
φ
6.4 0
φ
9.5 0
φ
12.7 0
φ
15.9 0
φ
19.1 1/2H
φ
22.2 1/2H
φ
25.4 1/2H
φ
28.6 1/2H
φ
31.8 1/2H
φ
34.9 1/2H
φ
38.1 1/2H
φ
41.3 1/2H