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• In the circumstances listed below, do not reuse the refrigerant piping as it is but wash it thoroughly before reusing it.
- Pump down operation cannot be performed for the existing air conditioner.
- The compressor has a failure history.
- Oil is discolored.
- The existing air conditioner is gas/oil heat pump type.
- Refrigerant oil used for the existing air conditioner is other than “ester oil, ethereal oil, ATMOS, SUNISO or H.A.B”.
• Do not reuse the flare to prevent gas leak. Make sure to install a new flare.
• If there is a welded part on the existing refrigerant piping, conduct a gas leak check on the welded part.
• Replace deteriorated heat insulating material with a new one. Heat insulating material is required for both liquid-side and gas-
side piping.
10.2.7. Refrigerant Piping Size And Allowable Piping Length
1. Refrigerant piping size
• In case of new installation, make sure to use standard piping size.
• In case of reuse of existing piping, the size must be within the range of refrigerant piping size combination as specified in the
above table.
2. Allowable piping length
3. Additional limitations for twin-type
Outdoor unit capacity Liquid-side applicable piping size (mm)
1 size down Standard 1 size up
YL34, YL43 type *2 ø6.35 x t0.8 ø9.52 x t0.8 ø12.7 x t0.8
Outdoor unit capacity Gas-side applicable piping size (mm)
1 size down Standard 1 size up
YL34, YL43 type — ø15.88 x t1.0 *1
*2
(ø19.05 x t1.0)
However: *1 As the design pressure is 4.15MPa, reuse of existing piping is not allowed if the ø19.05 existing piping is of 0 temper
material. In the case where ø19.05 existing piping is of 1/2H temper material, its reuse is allowed if the length is within
the allowable piping length as specified in the table below.
*2 Combination of ø6.35 on the liquid-side and ø19.05 on the gas-side cannot be used.
Pipe diameter Gas side Standard 1 size up
Liquid side 1 size down Standard 1 size up Standard 1 size up
Allowable piping length (min. ~ max.) 7.5m ~ 10m 7.5m ~ 50m 7.5m ~ 25m 7.5m ~ 25m 7.5m ~ 25m
Height difference
between indoor and
outdoor unit
Outdoor unit is
located on upper side
5m or less 30m or less 15m or less 15m or less 15m or less
Outdoor unit is
located on lower side
5m or less 20m or less 10m or less 10m or less 10m or less
Pipe diameter Gas side Standard 1 size up
Liquid side 1 size down Standard 1 size up Standard 1 size up
Allowable piping length Lo + La + Lb 7.5m ~ 10m 7.5m ~ 50m 7.5m ~ 25m 7.5m ~ 25m 7.5m ~ 25m
Max. allowable
one-way piping length
Lo + La
Lo + Lb
10m or less 40m or less 20m or less 20m or less 20m or less
Branch pipe length La , Lb 5m or less 20m or less 10m or less 10m or less 10m or less
Difference in branch
pipe lengt
La - Lb 3m or less 10m or less 5m or less 5m or less 5m or less
Height
difference
H2
Height
difference
between indoor
and outdoor
unit
Outdoor unit is
located on upper side
5m or less 30m or less 15m or less 15m or less 15m or less
Outdoor unit is
located on lower side
5m or less 20m or less 10m or less 10m or less 10m or less
H1 Height difference between indoor units 0.5m or less 0.5m or less 0.5m or less 0.5m or less 0.5m or less
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