5 Piping installation
Installation manual
8
35A5V1B
R32 Split series
3P650253-15Q – 2022.12
5
Piping installation
5.1
Preparing refrigerant piping
5.1.1
Refrigerant piping requirements
NOTICE
The piping and other pressure-containing parts shall be
suitable for refrigerant. Use phosphoric acid deoxidised
seamless copper for refrigerant piping.
▪
Piping material:
phosphoric acid deoxidised seamless copper
▪
Flare connections:
Only use annealed material.
▪
Piping diameter:
Liquid piping
Gas piping
Ø6.4 mm (1/4")
Ø9.5 mm (3/8")
▪
Piping temper grade and thickness:
Outer diameter
(Ø)
Temper grade
Thickness (t)
(a)
6.4 mm (1/4")
Annealed (O)
≥0.8 mm
t
Ø
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 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
(Ø
p
)
Insulation inner
diameter (Ø
i
)
Insulation thickness
(t)
6.4 mm (1/4")
8~10 mm
≥10 mm
9.5 mm (3/8")
10~14 mm
≥13 mm
Ø
i
Ø
i
t
Ø
p
Ø
p
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.
5.1.3
Refrigerant piping length and height
difference
What?
Distance
Maximum allowable pipe length
20 m
Minimum allowable pipe length
1.5 m
Maximum allowable height difference
15 m
5.2
Connecting the refrigerant piping
DANGER: RISK OF BURNING/SCALDING
CAUTION
▪ No brazing or welding on site for units with R32
refrigerant charge during shipment.
▪ During installation of the refrigeration system, joining of
parts with at least one part charged shall be performed
taking into account the following requirements: inside
occupied spaces non-permanent joints are NOT
allowed for R32 refrigerant except for site made joints
directly connecting the indoor unit to piping. Site made
joints directly connecting piping to indoor units shall be
of non-permanent type.
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
▪ 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.
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.
