28
5.7
Piping
Connections
Between
Outdoor
Units
The
piping
connecting
the
outdoor
units
should
be
horizontal
and
must
not
be
higher
than
the
refrigerant
outlets.
If
necessary,
to
avoid
obstacles
the
piping
may
be
vertically
offset
below
the
outlets.
When
inserting
a
vertical
offset
to
avoid
an
obstacle,
the
whole
outdoor
piping
should
be
offset,
rather
than
just
the
section
adjacent
to
the
obstacle.
Refer
to
Figure
3
‐
5.10.
Figure
3
‐
5.10:
Piping
connections
between
outdoor
units
Outdoor
piping
should
be
installed
in
a
metal
casing
to
protect
against
exposure
to
sunlight,
rain,
wind
and
other
potential
causes
of
damage.
5.8
Pipe
Flushing
5.8.1
Purpose
To
remove
dust,
other
particles
and
moisture,
which
could
cause
compressor
malfunction
if
not
flushed
out
before
the
system
is
run,
the
refrigerant
piping
should
be
flushed
using
nitrogen.
As
described
in
Installation
Manual,
5.1.1
“Installation
procedure”,
pipe
flushing
should
be
performed
once
the
piping
connections
have
been
completed
with
the
exception
of
the
final
connections
to
the
indoor
units.
That
is,
flushing
should
be
performed
once
the
outdoor
units
have
been
connected
but
before
the
indoor
units
are
connected.
