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Precautions to wiring connection between units
• Do not connect the power supply to the single-phase wiring
terminals.
Otherwise, the whole system will be damaged.
• The wiring from the indoor unit must be connected to the PC
board terminal F1/F2 (TO IN/D UNIT) of the outdoor unit.
• For the electric wires between units, after being secured within
the unit, wrap them together with the refrigerant piping connected
locally using the protective tape as shown in the figure below.
Liquid side piping
Protective tape
7.
REFRIGERANT PIPING CONNECTION
7-1 Installation tools
To withstand the pressure and prevent entry of any impurities
into the air conditioning system, always use the special
installation tools for R410A.
• To withstand the pressure and prevent entry of
any impurities (mineral oils such as specialized
Multi-purpose
lubricating oil and moisture), be sure to use the
gauge hose
special installation tools for R410A.
(Screw specifications for R410A and R407C are
different.)
• Make sure that the engine oil in the pump will not
flow backward into the air conditioning system
when the pump stops.
Vacuum pump
• Use the vacuum pump able to lower the pressure
to -100.7Pa (5Torr, -755mmHg).
7-2 Selecting piping material
• Do not use the pipes covered with sulfur, iron oxide, dust, cutting
oil, moisture or other contamination inside. (Better not to exceed
30mg/10m for the oil inside the pipes).
• Select a thickness for the refrigerant piping in accordance with
the local laws and regulations.
For R410A, the design pressure is 4.0 MPa.
• Use the refrigerant piping with its thickness complying with
Japan's High-Pressure Gas Control Law (January 2003).
• Thickness and size: determine them based on the precautions
for piping size selection on the back.
• While performing the piping work, make sure that the piping is
within the maximum allowable ranges for length, height in
difference and branch piping length listed on the back.
7-3 Piping protection
• Maintain and protect the piping to prevent moisture from getting
into and the entry of the impurities and dust, etc.
• Pay special caution when penetrating the copper pipes through
the walls till outside.
Location
Installation schedule
More than a month
Outdoor
Less than a month
Indoor
Random
10
Gas side piping
Electric wires
between units
Insulating material
Protection measure
Pinch
Pinch or seal with tape
7-4 Pipe connection
• Before removing the pinched piping (large)
1. Remove the valve lid, and check the stop valve is completely
closed.
2. Connect a vacuum gauge to the service port, and check
there is no residual pressure.
3. Cut off the pinched piping (small) with a vice, and check
there is no residual pressure again.
Cutting part
Piping under
the cutting part
Clamp the lower
After cutting off,
part of the cutting
check the residual
part with the vice,
oil and gas coming
then wrench from
out from the
left to right to cut
incision completely.
off directly.
[ To open ]
1. Open the valve lid and turn the shaft counter clockwise with the
inner hexagon wrench (JISB4648).
2. Turn it until the shaft stops.
3. Tighten the valve lid. (Refer to the column "Tightening torque"
for the tightening torque.)
Pinched piping (large)
[ To close ]
1. Open the valve lid and turn the shaft clockwise with the inner
hexagon wrench (JISB4648).
2. Tighten the valve safely until it contacts with the gasket of the
valve body.
3. Tighten the valve lid. (Refer to the column "Tightening torque"
for the tightening torque.)
WARNING
While removing the pinched piping (large), the residual gas and
oil remained in the piping of the valve body may cause the stop
valve cracks, and the flames of the latter may result in burns
also.
• Before brazing the removed pinched piping (large) and field
piping connection
Take cooling measures for the stop valves (such as wrapping a
wet and dripless cloth to them). Failure to do so will result in
damage to the valve body and cause the system leaks.
• Brazing piping locally (liquid side and gas side)
1. Remove the two piping cover plates under the unit.
2. When brazing, it is necessary to penetrate the electrode
from the front of the unit and the welding torch from the right
side to braze with the flames facing outside and avoid the
compressor sound-proof material and other piping.
(Refer to the figure on next page)
Note
1. B efore brazing, peel off the caution label and check there
is no residual tape.
Otherwise, it will adversely affect the brazing.
2. B raze the liquid side piping (thin) and the gas side piping
(thick) in order.
Brazing methods are same for the two.
Incision
Cut at the middle
of the pinched
piping (small)
using the vice's
cutting part.
Service port
On
Valve lid
Off
Cut off here
Pinched piping
(small)
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