Additional Installation Site Requirements Of The Outdoor Unit In Cold Climates; Preparing Refrigerant Piping; Refrigerant Piping Requirements; To Select The Piping Size - Daikin VRV IV RXMLQ8T7Y1B Series Installation And Operation Manual

4.1.2 Additional installation site requirements
of the outdoor unit in cold climates
NOTICE
When operating the unit in a low outdoor ambient
temperature with high humidity conditions, make sure to
take precautions to keep the drain holes of the unit free by
using proper equipment.
In heating:
20
15.5
15
10
5
a b
0
–5
–10
–15
–20
–25
10 15 20
T (°C DB)
AI
a Warming up operation range
b Operation range
T Ambient indoor temperature
AI
T Ambient outdoor temperature
AO
4.2

Preparing refrigerant piping

4.2.1

Refrigerant piping requirements

NOTICE
Refrigerant R410A requires strict cautions for keeping the
system clean and dry. Foreign materials (including mineral
oils or moisture) should be prevented from getting mixed
into the system.
NOTICE
The piping and other pressure-containing parts shall be
suitable for refrigerant. Use phosphoric acid deoxidised
seamless copper for refrigerant.
▪ Foreign materials inside pipes (including oils for fabrication) must
be ≤30 mg/10 m.
▪ Temper grade: use piping with temper grade in function of the
pipe diameter as listed in table below.
Pipe Ø Temper grade of piping material
≤15.9 mm
≥19.1 mm
▪ All piping lengths and distances have been taken into
consideration (see About the piping length in the installer
reference guide).
▪ Only use phosphoric acid deoxidised seamless copper.
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543426-1 – 2018.07
25 27 30
O (annealed)
1/2H (half hard)
4.2.2

To select the piping size

Determine the proper size using the following tables and reference
figure (only for indication).
A
a x
D F
b 3
G
E
1 2 4 5
1,2 VRV DX indoor unit
3 BP box
4,5 RA DX indoor unit
a,b Indoor branch kit
x,y Outdoor multi connection kit
A, B, C: Piping between outdoor unit and (first)
refrigerant branch kit
Choose from the following table in accordance with the outdoor unit
total capacity type, connected downstream.
Outdoor unit Piping outer diameter size (mm)
capacity type (HP)
Gas pipe
8
10
12~16
18~22
24
26~34
36~42
D: Piping between refrigerant branch kits
Choose from the following table in accordance with the indoor unit
total capacity type, connected downstream. Do not let the
connection piping exceed the refrigerant piping size chosen by the
general system model name.
Indoor unit capacity Piping outer diameter size (mm)
index
Gas pipe
<150
150≤x<200
200≤x<290
290≤x<420
420≤x<640
640≤x<920
≥920
Example:
▪ Downstream capacity for E=capacity index of unit 1
▪ Downstream capacity for D=capacity index of unit 1+capacity
index of unit 2
E: Piping between refrigerant branch kit and
indoor unit
Pipe size for direct connection to indoor unit must be the same as
the connection size of the indoor unit (in case indoor unit is VRV DX
indoor or Hydrobox).
4 Preparation
B B B
C y
Liquid pipe
19.1 9.5
22.2 9.5
28.6 12.7
28.6 15.9
34.9 15.9
34.9 19.1
41.3 19.1
Liquid pipe
15.9 9.5
19.1
22.2
28.6 12.7
15.9
34.9 19.1
41.3
Installation and operation manual
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