Panasonic U-72MF1U9 Technical Data Manual page 37

2. System Design
2-3. Installing Distribution Joint
Pay special attention to any
CAUTION location, such as a basement,
etc., where leaking refrigerant
can accumulate, since
refrigerant gas is heavier than
air.
(1) Refer to "HOW TO ATTACH DISTRIBUTION JOINT"
enclosed with the optional distribution joint kit (CZ-
P900PH1U, P224BH1U, P680BH1U, P1350BH1U).
(2) When creating a branch using a commercially available
T-joint (header joint system), orient the main tubing so that
it is either horizontal (level) or vertical. In order to prevent
accumulation of refrigerant oil in stopped units, if the main
tubing is horizontal then each branch tubing length "B"
should be at an angle that is greater than horizontal. If the
main tubing is vertical, provide a raised starting portion for
each branch.
When only one indoor unit is connected to the side of "A"
install part "A" at a positive angle (15-30°) for the fi eld tubing
as shown in the fi gure.
[Header joint system]
Be sure to solidly weld shut the T-joint end (marked by "X"
in the fi gure). In addition, pay attention to the insertion
depth of each connected tube so that the fl ow of refrig-
erant within the T-joint is not impeded.
When using the header joint system, do not make fur-
ther branches in the tubing.
Do not use the header joint system on the outdoor unit
side.
(3) If there are height differences between indoor units or if
branch tubing that follows a distribution joint is connected
to only 1 unit, a trap or ball valve must be added to that
distribution joint. (When adding the ball valve, locate it within
15 - 3/4" of the distribution joint.)
If a trap or ball valve is not added, do not operate the
system before repairs to a malfunctioning unit are
completed. (The refrigerant oil sent through the tubing
to the malfunctioning unit will accumulate and may
damage the compressor.)
Tube branching methods (horizontal use)
Arrow view D
B
view D
Header joint system (Indoor)
Outdoor
Indoor
Horizontal
line
L3 6.56 ft.
Types of vertical trap specifications
(When using ball valve)
Main tubing
Ball valve
(BV: purchased
separately)
Indoor unit (1)
(When not using ball valve)
Main tubing
Branch tubing is
directed upward.
More than
7–7/8"
Indoor unit is directed downward
2 - 23
Design of 3WAY VRF SYSTEM
A
B
Arrow view C
B
A
Horizontal
line
View as seen
from arrow
view C
Install at a
positive angle
Indoor
Install at a
positive angle
(15 – 30°)
Indoor
Solidly welded
Horizontal
line
shut (X)
Indoor unit (more than 2 units)
(If only 1 unit is connected, a ball valve
is also needed on this side.)
Horizontal
Indoor unit
(Each unit is connected
to tubing that is either
level or is directed
downward.)
A
1
2
3
4
5
6
7
8