Daikin R-410A Installation Manual page 27

Installation
1. To avoid the risk of oil retention in the piping, the piping
between the outdoor units must be routed level or slightly
upward.
Pattern 1
to indoor unit
Piping between outdoor units
to indoor unit
Pattern 2
to indoor unit
to indoor unit
Change to pattern 1 or pattern 2
Prohibited pattern
to indoor unit
to indoor unit
2. To avoid the risk of oil retention in the stopping unit, always
connect the stop valve and the piping between outdoor
units as shown in the figure A or figure B.
A
B
26
Piping between outdoor units
Downward inclination
Downward inclination
Oil remains in piping
A
B
Prohibited pattern
to indoor unit
to indoor unit
Oil remains in the stopping outdoor unit.
Change to pattern 1 or pattern 2
Unit A
Unit B
to indoor unit
Oil remains in the outdoor unit B when the system stops.
Change as shown in the figure below.
to indoor unit
3. If the connecting pipe length between outdoor units
exceeds 80 inches, it is necessary to install a vertical loop
in the gas line at least 8 inches in height and not more than
80 inches from the main outdoor unit closest to the first
connected indoor unit. See following diagram:
If 80 in. or less
Piping between outdoor units
to indoor unit
If 80 in. or more
Piping between
outdoor units
EDUS39-605
Unit A
Unit B
to indoor unit
Rising height:
8 in. or more
to indoor unit
80 in. or less
Rising height:
8 in. or more
80 in.
80 in. or less
or more
Installation