27
14.2.2.2 Method of piping flaring connection
Align the center of the pipes.
Sufficiently tighten the flare nut with your hand, and then
tighten it with a spanner and torque wrench.
The protective nut is a single-use part; it cannot be reused.
If it is removed, it shall be replaced with a new one.
Bar
Copper pipe
Clamp handle
Red arrow mark
Cone
Bracket
Handle
Bar
"A
"
IDU tubing
Flare nut Piping
Protective nut
Figure 14-12
● Excessive torque can break the nut during
installation.
● When flared joints are reused indoors, the
flaring part shall be re-fabricated.
Caution
14.3 Checking Refrigerant Piping
14.3.1 Refrigerant Piping Settings
(See Figure 14-13)
14.3.2 Flushing Pipes
To remove dust, other particles and moisture, which could
cause compressor malfunction if not flushed out before
the system is run, the refrigerant piping should be flushed
using nitrogen. Pipe flushing should be performed once
the piping connections have been completed with the
exception of the final connections to the indoor units.
That is, flushing should be performed once the outdoor
units have been connected but before the indoor units
are connected.
Pressure gauge
Yellow hose
Blue hose Red hose
ODU unit
Field piping
Nitrogen gas cylinder
Indoor
unit A
Indoor
unit B
R32
refrigerant tank
Weighing scale
Vacuum pump
Figure 14-13
①
Gas pipe stop valve
②
Liquid pipe stop valve
Only use nitrogen for flushing. Using carbon
dioxide risks leaving condensation in the piping.
Oxygen, air, refrigerant, flammable gases and
toxic gases must not be used for flushing. Use of
such gases may result in fire or explosion.
CAUTION
The liquid and gas sides must be flushed
simultaneously.
The flushing procedure is as follows:
1.Cover the inlets and outlets of the indoor units to
prevent dirt getting blown in during pipe flushing. (Pipe
flushing should be carried out before connecting the
indoor units to the piping system.)
2.Attach a pressure reducing valve to a nitrogen cylinder.
3.Connect the pressure reducing valve outlet to the inlet
on the liquid (or gas) side of the outdoor unit.
4.Use blind plugs to block all liquid (gas) side openings,
except for the opening at the indoor unit which is furthest
from the outdoor units (“Indoor unit A” in Fig.14-14).
5.Start to open the nitrogen cylinder valve and gradually
increase the pressure to 0.5Mpa.
6.Allow time for nitrogen to flow as far as the opening at
indoor unit A.
7.Flush the first opening:
a)Using suitable material, such as a bag or cloth, press
firmly against the opening at indoor unit A.
b)When the pressure becomes too high to block with
your hand, suddenly remove your hand allowing gas to
rush out.
c)Repeatedly flush in this manner until no further dirt or
moisture is emitted from the piping. Use a clean cloth to
check for dirt or moisture being emitted. Seal the opening
once it has been flushed.
8.Flush the other openings in the same manner, working
in sequence from indoor unit A towards the outdoor units.
Refer to Fig.14-15
9.Once flushing is complete, seal all openings to prevent
dust and moisture from entering.
Pressure gauge
Yellow hose
Blue hose Red hose
ODU unit
Field piping
Indoor
unit A
Indoor
unit B
Nitrogen gas cylinder
Fig. 14-14
①
Gas pipe stop valve
②
Liquid pipe stop valve
Fig.
14-15
Summary of Contents for KMF-80 DVR5
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