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5
Piping installation
5.1
Preparing refrigerant piping
5.1.1
Refrigerant piping requirements
▪ Piping material: phosphoric acid deoxidised seamless copper
▪ Piping diameter:
Liquid piping
Ø6.4 mm (1/4")
▪ Piping temper grade and thickness:
Outer diameter
Temper grade
(Ø)
6.4 mm (1/4")
Annealed (O)
9.5 mm (3/8")
Annealed (O)
(a)
Depending on the applicable legislation and the maximum
working pressure of the unit (see "PS High" on the unit name
plate), larger piping thickness might be required.
5.1.2
Refrigerant piping length and height
difference
What?
Maximum allowable pipe length
Minimum allowable pipe length
Maximum allowable height difference
5.1.3
Refrigerant piping insulation
▪ Use polyethylene foam as insulation material:
▪ with a heat transfer rate between 0.041 and 0.052 W/mK (0.035
and 0.045 kcal/mh°C)
▪ with a heat resistance of at least 120°C
▪ Insulation thickness:
Pipe outer diameter
Insulation inner
(Ø
)
diameter (Ø
p
6.4 mm (1/4")
8~10 mm
9.5 mm (3/8")
12~15 mm
Ø
Ø
i
i
Ø
Ø
p
p
t
If the temperature is higher than 30°C and the humidity is higher
than RH 80%, the thickness of the insulation materials should be at
least 20 mm to prevent condensation on the surface of the
insulation.
5.2
Connecting the refrigerant piping
DANGER: RISK OF BURNING/SCALDING
5.2.1
About connecting the refrigerant piping
Before connecting the refrigerant piping
Make sure the outdoor and indoor unit are mounted.
Typical workflow
Connecting the refrigerant piping involves:
▪ Connecting the refrigerant piping to the indoor unit
(A)RXP20~35N5V1B9
R32 split series
3P748643-2 – 2023.07
Gas piping
Ø9.5 mm (3/8")
(a)
Thickness (t)
Ø
≥0.8 mm
t
Distance
20 m
1.5 m
12 m
Insulation thickness
)
(t)
i
≥10 mm
▪ Connecting the refrigerant piping to the outdoor unit
▪ Insulating the refrigerant piping
▪ Keeping in mind the guidelines for:
▪ Pipe bending
▪ Flaring pipe ends
▪ Using the stop valves
5.2.2
Precautions when connecting the
refrigerant piping
DANGER: RISK OF BURNING/SCALDING
NOTICE
▪ Use the flare nut fixed to the main unit.
▪ To prevent gas leakage, apply refrigeration oil only to
the inside of the flare. Use refrigeration oil for R32
(Example: FW68DA).
▪ Do NOT reuse joints.
WARNING
Connect the refrigerant piping securely before running the
compressor. If the refrigerant piping is NOT connected and
the stop valve is open when the compressor is run, air will
be sucked in. This will cause abnormal pressure in the
refrigeration cycle, which may result in equipment damage
and even injury.
5.2.3
To connect the refrigerant piping to the
outdoor unit
▪ Piping length. Keep field piping as short as possible.
▪ Piping protection. Protect the field piping against physical
damage.
1 Connect the liquid refrigerant connection from the indoor unit to
the liquid stop valve of the outdoor unit.
a
c b
a
Liquid stop valve
b
Gas stop valve
c
Service port
2 Connect the gas refrigerant connection from the indoor unit to
the gas stop valve of the outdoor unit.
NOTICE
It is recommended that the refrigerant piping between
indoor and outdoor unit is installed in a ducting or the
refrigerant piping is wrapped with finishing tape.
5.3
Checking the refrigerant piping
5.3.1
To check for leaks
NOTICE
Do NOT exceed the unit's maximum working pressure (see
"PS High" on the unit name plate).
5 Piping installation
Installation manual
9
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