Hitachi FSXN1E Series Installation And Operation Manual page 45

Piping work and refrigerant charge
8.1.6 General instructions on the installation of refrigerant pipes
The copper pipe used for the installation must be specific for refrigeration systems: see on
The diameter of the refrigerant pipes depends directly on the power of the outdoor unit. The pipe diameter allocated must be respect-
ed, in line with the instructions given in chapter
The units must be located and the gas pipes laid, particularly when the outdoor unit is at a different height to the indoor unit, in line with
the instructions given in chapter
System performance depends on the distance between the outdoor and indoor unit. This aspect must be taken into account for the
installation of the refrigerant pipe. The outdoor units are factory-charged with sufficient refrigerant for a standard installation of certain
characteristics. Where the system installation requirements involve an increase in the distance between the outdoor and indoor unit,
refrigerant must be added to the installation in line with the instructions given in chapter

Flared connection mounting
Apply a thin layer of oil to the cone opening for refrigeration sys-
tems.
Line up the end of the flared pipe to face the fitting to which it is
to be threaded.
Gently rest the female cone on the male cone and check that the
measurement is correct. Keep the connection lined up with one
hand and gently thread on the flare nut with the other.
Tighten the connection to the corresponding tightening torque in-
dicated in the table below.
Nominal diameter
mm Inches
ø6.35
ø9.52
ø12.7
ø15.88
ø19.05
ø22.2
ø25.4
ø28.58
C A U T I O N
• Secure the fixed connection with a suitable wrench and use
a torque wrench to tighten the flare nut on the threaded con-
nections.
• Do not exceed the torque value indicated in the table. The
fitting can become misshapen and the connection may leak.
31
PMML0294A_rev.2_02-2014.indb 31
Pipe size
Precautions for the installation of the outdoor
Tightening torque
1/4 20 Nm
3/8 40 Nm
1/2 60 Nm
5/8 80 Nm
3/4 100 Nm
7/8 –
1 –
1-1/8 –
PMML0294A rev.2 - 07/2014
selection.
unit.

Refrigerant pipe insulation
The refrigerant circulates through the pipes at a very low tem-
perature (several degrees below zero, depending on the time of
year and the installation). The difference in temperature with the
ambient air is extremely large and causes two significant phe-
nomena to be taken into account:
• Cold irradiation along the entire pipe.
• Condensation of the humidity in the surrounding air.Actually,
cold irradiation is the temperature gain experienced by the
gas, as when it circulates under pressure and at such low
temperatures along the inside of the pipes, it is actually liquid
and obtains the outdoor temperature (boiling at a very low
temperature) to turn into gas.
As a result of the temperature gain (although it is actually per-
ceived as cold emission), it loses its capacity to cool and the sys-
tem does not perform as expected. Furthermore, the humidity in
the surrounding air condenses on the pipe and the greater the
temperature difference and the longer the pipe, the more water
is produced.
In view of this, the refrigerant pipes must be fitted with a suitable
insulation system that prevents the increase in temperature of the
refrigerant and the subsequent loss of energy and the condensa-
tion of water along the entire pipe.
Refrigerant pipes must always be separately insulated, using
closed cell insulation foam designed especially for refrigeration.
This insulation foam, supplied by the installer, can be obtained in
different formats. The most common is in the form of sheets and
rolls of tubes of different diameters.
Furthermore, all connections between the different sections of in-
sulation tubes must be reinforced with adhesive tape of the same
characteristics.
Once all of the unit installation and adjustment work is complete,
all threaded joints and valves must also be covered with adhesive
tape.
Copper pipes and sizes.
Refrigerant charge.
14/07/2014 12:28:20