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6.3. Pipe connection
6.3.1. Brazing
If air or different type of refrigerant enters the refrigeration cycle, the internal pres-
sure in the refrigeration cycle will become abnormally high and prevent the unit
from exerting its full performance.
Apply nitrogen gas while brazing the pipes.
Nitrogen gas pressure: 2.9 psi (0.02 MPa)
(= suffi cient pressure to be felt on
the back of your hand or more)
If a pipe is brazed without applying nitrogen gas, it will create an oxidation fi lm.
This can degrade performance or damage the parts in the unit (such as the com-
pressor or valves).
Do not use fl ux to braze pipes. If the fl ux is the chlorine type, it will cause the pipes
to corrode.
In addition, if the fl ux contains fl uoride, it will affect the refrigerant piping system due to
deterioration of refrigerant oil.
For brazing material, use phosphor copper that does not require fl ux.
6.3.2. Bending pipes
The pipes are shaped by your hands. Be careful not to collapse them. Do not bend the
pipes in an angle more than 90°.
When pipes are repeatedly bent or stretched, the material will harden, making it diffi cult
to bend or stretch them any more. Do not bend or stretch the pipes more than 3 times.
To prevent breaking of the pipe, avoid sharp bends. Bend the pipe with a radius of
curvature of 3-15/16 in (100 mm) or over.
If the pipe is bent repeatedly at the same place, it will break.
6.3.3. Pipe connection
The pipe can be connected by brazing
Suction gas pipe
Liquid pipe
Discharge gas pipe
Brazing
6.4. Installing heat insulation
Insulate the suction gas pipe, discharge gas pipe, liquid pipe, and gas pipe with heat
insulation.
Use heat insulation with heat resistance above 248 °F (120 °C).
In addition, if the humidity level at the installation location of the refrigerant piping is
expected to exceed 70%, install heat insulation around the refrigerant piping. If the
expected humidity level is 70-80%, use heat insulation that is 9/16 in (15 mm) or
thicker and if the expected humidity exceeds 80%, use heat insulation that is 13/16 in
(20 mm) or thicker.
If heat insulation is used that is not as thick as specifi ed, condensation may form on
the surface of the insulation. In addition, at 68°F (20 °C), use heat insulation with heat
conductivity of 0.045 W/(m·K) or less.
6.4.1. Piping insulation
(1) After the sealing test is complete, carry out insulation work.
(2) Insulate all pipes and piping connection parts so that there is no gap in it.
(3) Firmly connect the terminal part (a) so that no air comes in or out.
(4) Do not squeeze the cable ties excessively so as to ensure that the insulation mate-
rial is thick.
(a)
RB Unit
Cable tie (locally purchased)
• Wind the coupler heat insulation (accessories) around the strainer section of the
discharge gas piping.
En-7
CAUTION
Pressure regulating valve
Cap
Nitrogen gas
Brazing area
CAUTION
Gas pipe
RB
unit
Liquid pipe
Brazing
CAUTION
Insulation (locally purchased)
6.4.2. Installing cabinet insulation
If the relative humidity of the area may rise above 80%, install cabinet insulation (acces-
sories) in the following location:
Cabinet insulation
Install cabinet insulation under the
suction gas pipe on the connection
side of the outdoor unit.
7. ELECTRICAL WIRING
7.1. Safety precautions for electrical wiring
Electrical work must be performed in accordance with this Manual by a person
certifi ed under the national or regional regulations. Be sure to use a dedicated circuit
for the unit.
An insufficient power supply circuit or improperly performed electrical work can
cause serious accidents such as electric shock or fi re.
Before starting work, check that power is not being supplied to the RB unit, indoor
unit and outdoor unit.
For wiring, use the prescribed type of cables, connect them securely, making sure
that there are no external forces of the cables applied to the terminal connections.
Improperly connected or secured cables can cause serious accidents such as
overheating the terminals, electric shock, or fi re.
Securely install the electrical box cover on the unit.
An improperly installed electrical box cover can cause serious accidents such as
electric shock or fi re through exposure to dust or water.
Use the included connection cables and power cables or ones specified by the
manufacturer. Improper connections, insufficient insulation, or exceeding the
allowable current can cause electric shock or fi re.
Do not modify the power cables, use extension cables, or use any branches in the
wiring. Improper connections, insufficient insulation, or exceeding the allowable
current can cause electric shock or fi re.
Match the terminal block numbers and connection cable colors with those of the
indoor unit or outdoor unit. Erroneous wiring may cause burning of the electric parts.
Securely connect the connection cables to the terminal board. In addition, secure
the cables with wiring holders. Improper connections, either in the wiring or at the
ends of the wiring, can cause a malfunction, electric shock, or fi re.
Always fasten the outside covering of the connection cable with the cable clamp. (If
the insulator is chafed, electric discharge may occur.)
We suggest installing GFEB breakers or follow local electrical code.
When installing this system, install using ground fault equipment breakers (GFEB) to
reduce the risk of leaking current which result in electric shock or potential fi re.
Always connect the ground (earth) cable.
Improper grounding (earthing) work can cause electric shocks.
Perform wiring work in accordance with standards so that the air conditioner can be
operated safely and positively.
If the supply cable is damaged, it must be replaced by the manufacturer, its service
agent or similarly qualifi ed persons in order to avoid a hazard.
[Unit: in (mm)]
0 to 3/16
(0 to 5)
Align the center of the cabinet insulation
with the suction gas pipe axis.
WARNING
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