Refrigerant Pipe Selection; Pipe Size Selection; Multikit Or Distributor Selection; Refrigerant Piping Range - Hitachi UTOPIA R32 Series Technical Catalogue

9 Piping work and refrigerant charge

Refrigerant pipe selection

9.1 Refrigerant pipe selection

9.1.1 Pipe size selection

Select the pipe size in line with the following instructions:
1 Between the outdoor unit and the branch pipe (multikit): select the same pipe connection size as for the outdoor unit.
2 Between the branch pipe (multikit) and the indoor unit: select the same pipe connection size as for the indoor unit.
3 Between branch pipes (multikits): select the pipe connection size according the equivalent indoor unit size if adding
up the units after the branch pipe.
!
C A U T I O N
• Do not use refrigerant pipe sizes other than those indicated in this Technical Catalogue. The diameter of the refrigerant pipes depends
directly on the outdoor unit capacity.
• If larger diameter gas refrigerant pipes are used, the circuit lubrication oil tends to separate from the gas carrying it. The compressor
will be seriously damaged due to a lack of lubrication.
• If smaller diameter gas refrigerant pipes are used, the gas or liquid refrigerant will have serious difficulties in circulating. System
performance will be affected. The compressor will run under more severe conditions than foreseen and will be damaged in a short
space of time.

9.1.2 Multikit or distributor selection

Pipe connection size on outdoor units, indoor units and the multikit or distributor vary according to the system.
The sizes of the indoor and outdoor units could be different.

9.2 Refrigerant piping range

9.2.1 Refrigerant piping length

The refrigerant piping between the indoor unit and the outdoor unit should be designed using the following chart.
Keep the design point within the area of the chart, which is showing the applicable height difference according to piping
length.
Height difference (m)
When outdoor unit
is installed higher
than indoor unit
When outdoor unit
is installed lower
than indoor unit
84 TCGB0136 rev.1 - 05/2021
Total length between outdoor unit and
each indoor unit.
4-6HP 3HP
DSW2 DSW302
Setting
before
shipment