Owner`s manual

20
ENGLISH
■ Fixing and Piping
• Piping must be performed by qualified personnel
according to good refrigeration system practices.
• Piping materials and insulation materials must be of
refrigerant quality.
• Select the pipe diameters according to the size of
unit and cut the pipe to design length by using pipe
cutter.
• Install the flare nuts and flare the end of the pipes.
• Check that no foreign bodies are inside the piping.
• Align the central of the connection pipes and tighten
the flare nut.
• Fix piping with pipe clamps and check that any pipe
vibrations cannot be transmitted to the building
structure.
• Connect the pipe correctly.
• Do not apply the excessive torque.
• Use an appropriate bending tool to form curves and
avoid over-tightening the refrigerant tubes.
• To prevent heat loss, the two lines must be insulated
separately.
■ Maximum Piping Length
See Technical Specification
The suction line must have a 2% gradient up to the
compressor on horizontal sections.
Where piping lengths are unusually long and include a
large number of oil traps, it may be necessary to adjust
to compressor charge.
NOTES
REFRIGERANT PIPING CONNECTIONS
■ Refrigerant charge to be added per extra
meter of piping length when more than 5
meters.
Prefabricated refrigerant piping is available as an acces-
sory. If this is not used, piping and insulating materials em-
ployed must be compatible with this type of installation.
The pre-charged outdoor unit does not require charging
if piping length is 5 m or less. However, the interconnect-
ing piping and the indoor unit must be pumped down
before releasing R-410A refrigerant into them from the
outdoor unit.
1. Remove the cap from the service valve.
2. Connect the line to a vacuum pump and pump
down to 5 Pa.
3. When pump down is finished, wait 15 minutes
to detect potential circuit leakage. Open service
valves on the outdoor unit.
Outdoor unit
Indoor unit
Gas line
Liquid line
R-410A
* Note: The expansion device is located in the outdoor unit.
High pressure
Pressure tap
Manifold
Low pressure
Liquid valve
Gas valve
L
L
H
D
Unit size
Models
12 18 24 30 36 48
(g/m) 30 30 65 90 90 90
J391_EN.indd 20 3/14/07 1:33:41 PM