Connection Kit Selection; Pipe Size Selection - Hitachi RAS-8FSXNS2E Installation & Operation Manual

3.1 Connection kit selection

!
CAUTION
When brazing pipes, always protect the surrounding elements of the working area in order to avoid
damage due to the high temperature of the flame.
The optional piping connection kit is required for the combination unit.
Operation mode
Heat pump system
Heat recovery system

3.2 Pipe size selection

Select the pipe size in line with the following instructions:
Between the outdoor unit and the branch pipe (multi-kit): select the same pipe connection size as
for the outdoor unit.
Between the branch pipe (multi-kit) and the indoor unit: select the same pipe connection size as
for the indoor unit.
!
CAUTION
• Do not use refrigerant pipe sizes other than those indicated in the technical information. The
diameter of the refrigerant pipes depends directly on the power of the outdoor unit.
• If larger diameter 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 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.
• The copper pipe used in the refrigeration installations is different to the copper pipe used in
installations carrying domestic or heating water.
PMML0628 rev.0 - 05/2023
Outdoor unit
outdoor units
26 - 48
50 - 54
56 - 72
74 - 96
20 - 24
26 - 36
38 - 54
26 - 48
50 - 54
20 - 24
26 - 36
38 - 54
Number of
Connection kit
2 MC-21AN1
3 MC-30AN1
3 MC-NP31SA
4 MC-NP40SA
2 MC-20AN1
2 MC-21AN1
3 MC-30AN1
2 MC-21XN1
3 MC-30XN1
2 MC-20XN1
2 MC-21XN1
3 MC-30XN1
3
13