Daikin Multi+ R32 Split Series, Installer'S Reference Manual

Page: 33 / 80

7 | Piping installation
Installer reference guide
33
4MWXM-A9
R32 Split series
4P708645-1 – 2022.09
Refrigerant piping material
▪ Piping material: phosphoric acid deoxidised seamless copper
▪ Flare connections: Only use annealed material.
▪ 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")
12.7 mm (1/2")
(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.
7.1.2 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") 12~15 mm ≥13 mm
12.7 mm (1/2") 14~16 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.
Use separate thermal insulation pipes for the gas and liquid refrigerant piping.
7.1.3 Refrigerant piping length and height difference
The shorter the refrigerant piping, the better the performance of the system.
The piping length and height differences must comply with the following
requirements.
Shortest allowable length per room is 3 m.
Refrigerant piping length to each indoor
unit Refrigerant piping total length
≤25 m ≤50 m
Height difference
outdoor-indoor Height difference indoor-
indoor
Outdoor unit installed
higher than indoor unit ≤15 m ≤7.5 m