Refrigerant Piping Work - Hitachi HRNM Serie Installations- Und Betriebshandbuch

PIPING AND REFRIGERANT CHARGE
20

12.1. REFRIGERANT PIPING WORK

12.1.1. PIPING MATERIALS
1. Prepare locally-supplied copper pipes.
2. Select the piping size with the correct thickness and
correct material which can have sufficient pressure
strength.
3. Select clean copper pipes. Make sure there is no dust
and moisture inside. Blow the inside of the pipes with
oxygen free nitrogen to remove any dust and foreign
materials before connecting pipes.
4. After connecting the refrigerant piping, seal the open
space between Knockout hole and refrigerant pipes
by using insulation material as shown bellow:
Insulation material
Unit
Side
Insulation material
NOTE:
A system with no moisture or oil contamination will
give maximum performance and lifecycle compared to
that of a poorly prepared system. Take particular care
to ensure all copper piping is clean and dry internally.
There is no refrigerant in the cycle of the indoor unit.
12.1.2. SUSPENSION OF REFRIGERANT PIPING
Suspend the refrigerant piping at certain points and prevent
the refrigerant piping from touching the weak part of the
building such as wall, ceiling, etc...
(If touched, abnormal sound may occur due to the vibration
of the piping. Pay special attention in case of short piping
length).
1~15m
Indoor Unit
Field-Supplied
Insulation material
Fire-Proof
Section
Treatment
CAUTION:
Cap the end of the pipe when pipe is to be inserted
through a hole
Do not put pipes on the ground directly without a cap
or vinyl tape at the end of the pipe
If piping installation is not completed until next day or
over a longer period of time, braze off the ends of the
piping and charge with oxygen free nitrogen through a
Schrader valve type access fitting to prevent moisture
and particle contamination.
Do not use insulation material that contains NH3
because it can damage cooper pipe material and can
be a source of future leakage.
Completely insulate both refrigerant gas piping and
liquid piping between the indoor unit(s) and the
outdoor unit.
If not insulated, dew will ocur on the piping surface
Do not fix the refrigerant piping directly with the metal
fittings (The refrigerant piping may expand and contract).
Some examples for suspension method are shown below.
For Suspending For Piping
Heavies Along The Wall
For Instant
Installation Work