DC Inverter Multi 
VRF Service Manual
97
4 INSTALLATION REQUIREMENTS OF REFRIGERANT PIPING
4.1 Specication 
R410a refrigerant system
External Diameter(mm/inch) Thickness(mm) External Diameter(mm/inch) Thickness(mm)
φ6.35
 0.8 φ25.4  1.5
φ9.52  0.8 φ28.6  1.5
φ12.7
 1 φ34.9  1.5
φ15.9
 1 φ41.3  2.0
φ19.05  1 φ44.5  2.0
φ22.2
 1.5 φ54.1  2.0
4�2 Allowable Length and Height Differences of the Refrigerant Piping between the Indoor and Outdoor Units 
Height difference between indoor unit and outdoor unit: H
The 1st 
branch section
Equivalent length of farthest pipe: L
The equivalent length of the farthest pipe from the 1st branch: L
The equivalent length is 0.5m for each Y-type branch pipe.
Outdoor unit
Indoor unit
Height difference 
between indoor units: H
L1
L2
L3
L4
L5
L6
L7
L8