1. Before use
77
9.Cabling
Check
that
cabling
will
not
be
subject
to
wear,corrosion,
excessive
pressure,
vibration,
sharp
edges
or
any
other
adverse
environmental
effects.
The
check
shall
also
take
into
account
the
effects
of
aging
or
continual
vibration
from
sources
such
as
compressors
or
fans.
10.Detection
of
flammable
refrigerants
Under
no
circumstances
shall
potential
sources
of
ignition
be
used
in
the
searching
for
or
detection
of
refrigerant
leaks.
A
halide
torch (or
any
other
detector
using
a
naked
flame)
shall
not
be
used.
11.Leak
detection
methods
The
following
leak
detection
methods
are
deemed
acceptable
for
systems
containing
flammable
refrigerants.
Electronic
leak
detectors
shall
be
used
to
detect
flammable
refrigerants,
but
the
sensitivity
may
not
be
adequate,
or
may
need
re-calibration. (Detection
equipment
shall
be
calibrated
in
a
refrigerant-free
area.)
Ensure
that
the
detector
is
not
a
potential
source
of
ignition
and
is
suitable
for
the
refrigerant
used.
Leak
detection
equipment
shall
be
set
at
a
percentage
of
the
LFL
of
the
refrigerant
and
shall
be
calibrated
to
the
refrigerant
employed
and
the
appropriate
percentage
of
gas (25
%
maximum)
is
confirmed.
Leak
detection
fluids
are
suitable
for
use
with
most
refrigerants
but
the
use
of
detergents
containing
chlorine
shall
be
avoided
as
the
chlorine
may
react
with
the
refrigerant
and
corrode
the
copper
pipe-work.
If
a
leak
is
suspected, all
naked
flames
shall
be
removed/
extinguished.
If
a
leakage
of
refrigerant
is
found
which
requires
brazing,
all
of
the
refrigerant
shall
be
recovered
from
the
system,
or
isolated (by
means
of
shut
off
valves)
in
a
part
of
the
system
remote
from
the
leak.
Oxygen
free
nitrogen (OFN)
shall
then
be
purged
through
the
system
both
before
and
during
the
brazing
process.
12.Removal
and
evacuation
When
breaking
into
the
refrigerant
circuit
to
make
repairs
–
or
for
any
other
purpose
–
conventional
procedures
shall
be
used.
However,
it
is
important
that
best
practice
is
followed
since
flammability
is
a
consideration.
The
following
procedure
shall
be
adhered
to:
•
Remove
refrigerant;
•
Purge
the
circuit
with
inert
gas;
•
Evacuate;
•
Purge
again
with
inert
gas;
•
Open
the
circuit
by
cutting
or
brazing.
The
refrigerant
charge
shall
be
recovered
into
the
correct
recovery
cylinders.
The
system
shall
be “flushed”
with
OFN
to
render
the
unit
safe.
This
process
may
need
to
be
repeated
several
times.
Compressed
air
or
oxygen
shall
not
be
used
for
this
task.
Flushing
shall
be
achieved
by
breaking
the
vacuum
in
the
system
with
OFN
and
continuing
to
fill
until
the
working
pressure
is
achieved,
then
venting
to
atmosphere,
and
finally
pulling
down
to
a
vacuum.
This
process
shall
be
repeated
until
no
refrigerant
is
within
the
system.
When
the
final
OFN
charge
is
used,
the
system
shall
be
vented
down
to
atmospheric
pressure
to
enable
work
to
take
place.
This
operation
is
absolutely
vital
if
brazing
operations
on
the
pipe-work
are
to
take
place.
Ensure
that
the
outlet
for
the
vacuum
pump
is
not
close
to
any
ignition
sources
and
there
is
ventilation
available.
Содержание Thermal 12
Страница 119: ...5 Maintenance 5 1 119 Cable connected to fan motor capacitor 4 ...
Страница 127: ...6 Attached drawing Monoblock unit 1 127 Thermal 6 9 12 ...
Страница 131: ......