(2) The distance between the unit bottom and the pipe (H) must be 0.2 m (7-7/8 in) or below. In the figure on the right, because the distance is
more than 0.2 m (7-7/8 in), the oil accumulates in Unit 1 when Unit 2 is in operation and Unit 1 is stopped.
Unit 1
Unit 2
Ⓐ
Unit 1
Unit 2
Ⓐ
H
H ≤ 0.2 m (7-7/8 in)
(3) The vertical separation between units (H) must be 0.1 m (3-15/16 in) or below. In the figure on the right, because the distance is more than
0.1 m (3-15/16 in), the oil accumulates in Unit 1 when Unit 2 is in operation and Unit 1 is stopped.
Unit 2
Unit 1
Unit 1
Ⓐ
H
H ≤ 0.1 m (3-15/16 in)
(4) The vertical separation between units (H) must be 0.1 m (3-15/16 in) or below. In the figure on the right, because the distance is more than
0.1 m (3-15/16 in), the oil accumulates in Unit 2 when Unit 1 is in operation and Unit 2 is stopped.
Unit 1
Unit 1
Unit 2
H
Ⓐ
H ≤ 0.1 m (3-15/16 in)
・The Twinning Kit must be installed horizontally using a level vessel to avoid unit damage.
Ⓑ
Ⓐ
・Do not install traps to prevent oil backflow and compressor start-up failure.
9-2. Pipe selection
Use refrigerant piping made of phosphorus deoxidized copper (copper and copper alloy seamless pipes) that
meets local requirements. Pipe joints should also meet local requirements. Keep the inner and outer surfaces
of the pipes clean and free of sulphur, oxides, dust/dirt, shaving particles, oils, moisture, or any other
contaminants.
- Contaminants on the inside of the refrigerant piping will cause the refrigerant oil to deteriorate and cause the
compressor to malfunction.
Use refrigerant pipes for use with R410A refrigerant system. Piping for systems for use with other types of refrigerants may not be able to be used.
Use refrigerant pipes with the thicknesses specified in the table below.
Size [mm (in)]
Radial thickness [mm (mil)]
ø6.35 (ø1/4)
ø9.52 (ø3/8)
ø12.7 (ø1/2)
ø15.88 (ø5/8)
ø19.05 (ø3/4)
ø22.2 (ø7/8)
ø25.4 (ø1)
ø28.58 (ø1-1/8)
ø31.75 (ø1-1/4)
ø34.93 (ø1-3/8)
ø41.28 (ø1-5/8)
WT09117X05
Unit 1
Ⓐ
H
H > 0.2 m (7-7/8 in)
Unit 1
Ⓐ
Unit 1
Ⓐ
H
Ⓐ
Twinning Kit
Ⓑ
Level vessel
Type
0.8 (32)
Type-O
0.8 (32)
Type-O
0.8 (32)
Type-O
1.0 (40)
Type-O
1.2 (48)
Type-O
1.0 (40)
Type-1/2H or H
1.0 (40)
Type-1/2H or H
1.0 (40)
Type-1/2H or H
1.0 (40)
Type-1/2H or H
1.1 (44)
Type-1/2H or H
1.2 (48)
Type-1/2H or H
1.4 (56)
Type-1/2H or H
Unit 2
Unit 2
H
H > 0.1 m (3-15/16 in)
Unit 2
H > 0.1 m (3-15/16 in)
GB-17