Hitachi RAS-10FSXNPE, Instruction Manual

Page: 34 / 170

8.2 PiPe size seleCtion
Select the pipe size in line with the following instructions:
1
Between the outdoor unit and the branch pipe (multi-kit):
select the same pipe connection size as for the outdoor unit.
2 Between the branch pipe (multi-kit) and the indoor unit:
select the same pipe connection size as for the indoor unit.
!
C a U t i o n
• 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.
!
C a U t i o n
• The copper pipe used in the refrigeration installations is different to
the copper pipe used in installations carrying domestic or heating
water.
• The copper pipe for refrigeration installations is especially treated for
outdoors and indoors. The interior surface finish makes it easier for
the refrigerant to circulate and withstands the action of the lubricant
oil applied to outdoor equipment.
Always use clean copper pipes with no signs of knocks or
cracks. Make sure there is no dust or dampness on the inside.
Before you install the pipes, clean the inside with oxygen-
free nitrogen gas to eliminate any remains of dust or other
substances.
!
C a U t i o n
• Do not use hand saws, circular saws, abrasive grinders or other tools
that generate shavings.
• Strictly follow national or local regulations regarding occupational
health and safety.
• Wear appropriate means of protection during cutting or brazing
operations and installation (gloves, eye protection, etc).
On completing the installation of the refrigerant pipes, insulate
them appropriately using suitable insulating material and seal
the open space between the holes made and the pipe.
8.2.1 Size of pipes (ø mm)
For heat pump systems (2 pipes)
For selecting the pipe sizes between the outdoor unit and the piping connection kit

, between the piping connection kits

and for
piping connection kit
Ⓐ
, refer to the items from “Connection of refrigerant pipes for heat pump system (2 pipes)” in the manual on
the CD-ROM.
1
D
5 5 5
5 5 5
4
C C
B
A A
1 1
4
4
3
2
Upstream side
Outdoor
unit A
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Outdoor
unit B
Outdoor
unit C
Piping connection
kit 2
First branch
Piping
connection kit 1
PIPING WORK AND REFRIGERANT CHARGE
PMML0479 rev.4 - 11/2018 12