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Table. A (Wall thickness and pipe material for each diameter)
Outside Diameter
in
(mm)
1/4
(6.35)
3/8
(9.52)
1/2
(12.70)
5/8
(15.88)
Wall Thickness (*2)
in
(mm)
0.032
(0.8)
0.032
(0.8)
0.032
(0.8)
0.039
(1.0)
Material
COPPER (*1) JIS H3300 C1220T-O or equivalent
Please select the pipe size in accordance with local rules.
*1: Allowable tensile stress ≥ 33 N/mm
*2: Endurance pressure of the pipes 609 psi (4.2 MPa)
Table. B (Diameter of piping used between outdoor unit and first separation
tubes or headers)
MODEL
Outdoor unit cooling
capacity [Btu]
Diameter of piping [in (mm)]
Liquid pipe Gas pipe
AOU36RLAVS4 36,000 3/8 (9.52) 5/8 (15.88)
AOU48RLAVS4 48,000 3/8 (9.52) 5/8 (15.88)
Table. C (Diameter of piping used between separation tubes)
Outside diameter [in (mm)]
Separation tube (*3) Header (*3)
Liquid pipe Gas pipe
3/8 (9.52) 5/8 (15.88) UTP-AX054A
UTR-H0906L
UTR-H0908L
*3: For the installation method, please refer to the installation manuals for indoor unit,
separation tubes or headers.
Use a standard separation tube for pipe branching. Do not use a T tube as it does not
separate the refrigerant evenly.
Table. D (Diameter of piping used between separation tube and indoor unit)
Cooling capacity of indoor unit [Btu]
Outside diameter [in (mm)]
Liquid pipe Gas pipe
4,000 / 7,500 / 9,500 / 12,000 / 14,000 1/4 (6.35) 1/2 (12.70)
18,000 / 24,000 / 30,000
3/8 (9.52)
5/8 (15.88)
36,000 / 48,000 / 60,000 (*4) 3/4 (19.05)
*4: If pipe diameter Table D > Table C , using of pipe size from Table C is preferable.
(Use reducer to change the diameter of connection pipe.)
When one indoor unit is connected to the outdoor unit.
• Please use a reducer (locally purchased) to match the piping diameter of the outdoor
unit to the indoor unit valve. Attach the reducer to the indoor unit valve.
• For the valve size of the indoor unit, refer to the installation manual of the indoor unit
or Design & Technical manual.
Connection example
Outdoor unit: AOU36RLAVS4 Indoor unit: ARUM36TLAV
Gas pipe size:
5/8 in (15.88 mm)
Gas valve size:
3/4 in (19.05 mm)
Reducer
(locally purchased)
4.3. Protection of pipes
Location Working period Protection method
Outdoor
1 month or more Pinch pipes
Less than 1 month Pinch or tape pipes
Indoor — Pinch or tape pipes
• Protect the pipes to prevent the entry of moisture and dust.
• Especially pay attention when passing the pipes through a hole or connecting the end of
a pipe to the outdoor unit.
5. PIPE INSTALLATION
5.1. Brazing
CAUTION
If air or another type of refrigerant enters the refrigera-
tion cycle, the internal pressure in the refrigeration
cycle will become abnormally high and prevent the
unit from exerting its full performance.
Pressure regulating valve
Cap
Nitrogen gas
Brazing area
Apply nitrogen gas while brazing the pipes.
Nitrogen gas pressure: 2.9 psi (0.02 MPa)
(= pressure felt sufficiently on the back of your hand)
If a pipe is brazed without applying nitrogen gas, it will create an oxidation film.
This can degrade performance or damage the parts in the unit (such as the compressor
or valves).
Do not use flux to braze pipes. If the flux is the chlorine type, it will cause the pipes to
corrode.
In addition, if the flux contains fluoride, it will affect the refrigerant piping system due to
deterioration of refrigerant oil.
For brazing material, use phosphor copper that does not require flux.
Installation in cold regions
When using in areas where the outside temperature is low, install a windbreak on the suc-
tion side of the outdoor unit to prevent it from being exposed to the wind.
CAUTION
If the outdoor unit is directly exposed to cold wind, there are the following risks.
• Reduced heating capacity due to poor defrosting.
• Damage to the outdoor unit due to the growth of icing.
Example of windbreak installation [unit: in (mm)]
8 (200)
12 (300)
8 (200)
Outdoor unit
Windbreak
Windbreak
Above the height of
the outdoor unit.
* Follow the requirements described in "3.2. Space requirement" when installing the
windbreak.
4. SYSTEM CONFIGURATION
4.1. System confi guration
CAUTION
Always keep to the limit on the total amount of refrigerant. Exceeding the limit on the
total amount of refrigerant when charging will lead to malfunction.
• Between outdoor unit and the farthest indoor unit
a + d ≤ 164 ft (50 m), a + h ≤ 164 ft (50 m)
• Between the first separation tube and the farthest indoor unit
d ≤ 131 ft (40 m), h ≤ 131 ft (40 m)
• Between the nearest indoor unit and the outdoor unit
a + b + e ≥ 16 ft (5 m), a + c + i ≥ 16 ft (5 m)
• Between outdoor unit and the first separation tube
a ≥ 9 ft (3 m)
• Difference in height between outdoor units and indoor units (H1)
98 ft (30 m) or less: Outdoor unit is higher than indoor unit
98 ft (30 m) or less: Outdoor unit is lower than indoor unit
• Difference in height between indoor units and indoor units
H2 ≤ 49 ft (15 m), H3 ≤ 49 ft (15 m)
• Maximum total equivalent pipe length
a + d + e + f + g + h + i + j + k ≤ 262 ft (80 m)
• Total refrigerant amount ≤ 15 lb (6.83 kg)
d
h
i
f
e
b
c
jk
H3
g
H1
H2
a
Outdoor unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Fig. A
4.2. Pipe selection
CAUTION
This unit is designed specifically for use with the R410A refrigerant.
Pipes for R407C or R22 may not be used with this unit.
Do not use existing pipes.
Improper pipe selection will degrade performance.
First separation
tube (optional)
Separation tube
(optional)
Pipe size
(table B)
Pipe size
(table C)
Pipe size
(table D)
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
Indoor
unit
9380545378-03_IM.indb 59380545378-03_IM.indb 5 2022/10/26 10:24:572022/10/26 10:24:57
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