Panasonic CU-YL28HBE5 Service Manual page 37

2. Allowable piping length
Pipe diameter
Allowable piping length (min. ~ max.)
Height difference
between indoor and
outdoor unit
3. Additional limitations for twin-type
Pipe diameter
Allowable piping length
Max. allowable
one-way piping length
Branch pipe length
Difference in branch
pipe lengt
Height H2 between indoor
difference
H1 Height difference between indoor units
10.1.7. Connecting The Pipes
• Use a clean pipe which does not include water or dust for inside of piping.
• When cutting the refrigerant pipes, a piping cutter must be used. Before connecting the refrigerant pipes, blow nitrogen and blow
off dust in the pipes.
(Never use tools which cause a lot of dust such as a saw and a magnet.)
• When waxing replace nitrogen inside the piping after removing dirt and dust. (In order to prevent oxidization scale from forming
inside the piping).
• The refrigerant pipes are of particular importance.
The installation work for refrigerant cycles in separate-type air conditioners must be carried out perfectly.
• Set the lower limit of the allowable pipe length to 7.5m.
If the pipe is shorter than 7.5m, the refrigerant may become overfilled and a problem such as abnormal high pressure could
occur.
1. Refer to the table below for the pipe diameters equivalent lengths and indoor/outdoor unit difference of elevation.
Pipe diameter (mm)
Liquid-side pipes
ø9.52 x t1.0
Gas side
Liquid side
Outdoor unit is
located on upper side
Outdoor unit is
located on lower side
Gas side
Liquid side
Lo + La + Lb
Lo + La
Lo + Lb
La , Lb
La - Lb
Height Outdoor unit is
difference located on upper side
Outdoor unit is
and outdoor
located on lower side
unit
Equivalent
length (m)
Gas-side pipes
ø15.88 x t1.2
1 size down
7.5m ~ 10m
5m or less
5m or less
1 size down
7.5m ~ 10m
10m or less
5m or less
3m or less
5m or less
5m or less
0.5m or less
• Maximum allowable one-way piping length is the larger
numerical value between (Lo + La) and (Lo + Lb).
• For twin type, only the main piping can be reused among
the existing piping. Brandnew standard pipe should be
installed for branch pipe/branch piping.
Outdoor unit on upper side
Difference of
elevation (m)
30
37
Standard
Standard
7.5m ~ 30m
25m or less
20m or less
Standard
Standard
7.5m ~ 30m
20m or less
10m or less
5m or less
25m or less
20m or less
0.5m or less
Outdoor unit on lower side
Difference of
elevation (m)
25
1 size up
7.5m ~ 15m
15m or less
10m or less
1 size up
7.5m ~ 15m
10m or less
10m or less
5m or less
15m or less
10m or less
0.5m or less
20