Daikin VRV III REMQ72PBYD Engineering Data page 53

Installation
(2) The piping between outdoor units must be installed level
(Pattern 1) or with a rise (Pattern 2). Otherwise oil may pool in
the pipes.
Pattern 1
Front connections
to indoor unit
Piping between outdoor units
Level
Side (bottom) connections
to indoor unit
Piping between outdoor units
Pattern 2
Front connections
to indoor unit
Rise
Side (bottom) connections
to indoor unit
Change to pattern 1 or pattern 2
Prohibited pattern
Front connections
Downward
Downward inclination
inclination
Side (bottom) connections
to indoor unit
Downward inclination
(3) To avoid the risk of oil detention in the stopping unit, always
connect the shutoff valve and the piping between outdoor units
as shown A or B in the figure below.
A
B
Front connections
52
Unit Unit
A B
Unit Unit
A B
Unit Unit
A B
Rise
Unit Unit
A B
Rise
Oil remains in piping
Unit Unit
to indoor
A B
unit
Unit Unit
A B
A
B
Side (bottom) connections
Prohibited pattern
Front connections
to indoor unit
Side (bottom) connections
to indoor unit
Oil remains in the stopping outdoor unit.
Change to pattern 1 or pattern 2
Unit
B
Unit
A
Oil remains in the unit A when system stops.
Change as shown in the figure below.
Connect straightly
Unit
B
Unit
A
(4) If the piping length between the outdoor units exceeds 80 in.,
create a rise of 8 in. or more in the gas piping under a length of
80 in. from the outdoor unit multi connection piping kit.
If less than 80 in.
Gas pipe between
outdoor units
to indoor unit
If 80 in. or more
Gas pipe between
outdoor units
to indoor unit
5.
Branching the refrigerant piping
Heed the restrictions below when installing the refrigerant
branching kit and read the installation instruction manual with the
kit.
(Improper installation could lead to malfunctioning or breakdown of
the outdoor unit.)
<REFNET joint>
Install the REFNET joint so it splits horizontally or vertically.
(Refer to figure 14)
1. Horizontal
2. A-arrow view
3. Horizontal surface
4. ±30° or less
5. Vertical
<REFNET header>
Install the REFNET header so it splits horizontally.
(Refer to figure 15)
1. Horizontal surface
2. B-arrow view
EDUS391004-N
Unit A Unit B
Unit A Unit B
Unit Unit
A A
Unit
B
Oil remains in the unit B when system stops.
Change as shown in the figure below.
Connect straightly Put rising
Unit Unit
A A
Unit
B
Rising height :
8 in. or more
Unit Unit
A B
less than 80 in.
Rising height :
Unit
8 in. or more
A
less than 80 in.
3P215731-10R
Installation of Outdoor Units
Unit
B
Unit
B
Unit
B