12
ENGLISH
Refrigerant piping on three principles
Drying Cleanliness Airtight
Should be no moisture
inside
No dust inside.
There is no refrigerant
leakage
Items
Cause
failure
- Significant hydroly-
sis of refrigerant oil
- Degradation of re-
frigerant oil
- Poor insulation of
the compressor
- Do not cold and
warm
- Clogging of EEV,
Capillary
- Degradation of re-
frigerant oil
- Poor insulation of
the compressor
- Do not cold and
warm
- Clogging of EEV,
Capillary
- Gas shortages
- Degradation of re-
frigerant oil
- Poor insulation of
the compressor
- Do not cold and
warm
Coun-
termea-
sure
-
No moisture in the pipe
- Until the connec-
tion is completed,
the plumbing pipe
entrance should be
strictly controlled.
- Stop plumbing at
rainy day.
- Pipe entrance
should be taken
side or bottom.
-
When removal burr
after cutting pipe,
pipe entrance should
be taken down.
- Pipe entrance
should be fitted
cap when pass
through the walls.
-
No dust in the pipe.
- Until the connec-
tion is completed,
the plumbing pipe
entrance should be
strictly controlled.
- Pipe entrance
should be taken
side or bottom.
- When removal
burr after cutting
pipe, pipe entrance
should be taken
down.
- Pipe entrance
should be fitted
cap when pass
through the walls.
- Airtightness test
should be.
- Brazing operations
to comply with
standards.
- Flare to comply
with standards.
- Flange connec-
tions to comply
with standards.
Nitrogen substitution method
Welding, as when heating without nitrogen substitution a large
amount of the oxide film is formed on the internal piping.
The oxide film is a caused by clogging EEV, Capillary, oil hole of accu-
mulator and suction hole of oil pump in compressor.
It prevents normal operation of the compressor.
In order to avoid this problem, Welding should be done after replacing
air by nitrogen gas.
When welding plumbing pipe, the work is required.
1 Always use the nitrogen.(not use oxygen, carbon dioxide, and
a Chevron gas): Please use the following nitrogen pressure
0.02 MPa Oxygen – Promotes oxidative degradation of refrig-
erant oil.
Because it is flammable, it is strictly prohibited to use Carbon
dioxide – Degrade the drying characteristics of gas Chevron
Gas – Toxic gas occurs when exposed to direct flame.
2 Always use a pressure reducing valve.
3
Please do not use commercially available antioxidant.
The residual material seems to be the oxide scale is observed.
In fact, due to the organic acids generated by oxidation of the
alcohol contained in the anti-oxidants, ants nest corrosion oc-
curs. (causes of organic acid ’ alcohol + copper + water +
temperature)
CAUTION
!
Regulator
Nitrogen gas Nitrogen gas
Pressure 0.02 MPa less Pressure 0.02 MPa less
Nitrogen gas
Pressure 0.02 MPa less
Auxiliary valve
Taping
(Should not
contain air)
Welding Point
Note) should not block the outlet side.
When the internal pressure in pipe is abo
ve the atmospheric pressure, pinhole is o
ccurred and it is a leakage cause.
Oxide scale
Nitrogen
CAUTION
Please block the pipe knock outs of the front and side panels after
installing the pipes.
(Animals or foreign objects may be brought in to damage wires.)
!
WARNING
• Always careful not to leak the refrigerant during welding.
• The refrigerant generates poisonous gas harmful to human body
if combusted.
• Do not perform welding in a closed space.
• Be sure to close the cap of the service port to prevent gas leak-
age after the work.
!
Gas pipe
Liquid pipe
Refrigerant
Charging Port
Service Port
REFRIGERANT PIPING INSTALLATION
Precautions on Pipe connection / Valve operation
Pipe connection is done by connecting from the end of the pipe to the
branching pipes, and the refrigerant pipe coming out of the outdoor
unit is divided at the end to connect to each indoor unit. Flare connec-
tion for the indoor unit, and welding connection for the outdoor pipe
and the branching parts.
- Use hexagonal wrench to open/close the valve.
P
lumbing materials and storage methods
Pipe must be able to obtain the specified thickness and should be
used with low impurities.
Also when handling storage, pipe must be careful to prevent a frac-
ture, deformity and wound.
Should not be mixed with contaminations such as dust, moisture.
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