28/61
Switch
on
crankcase
heaters
24
hours
before
start-up.
Check
that
the
condenser
fans
turn
freely.
Operating
instructions
during
maintenance
During
all
operations,
the
following
operating
instructions
must
be
followed:
-
Unit
doors
must
only
be
opened
after
the
main
switch
is
cut-off
and
the
fans
have
completely
stopped.
-
The
HP
and
LP
pressure
switches
can
be
accessed
with
the
doors
closed
through
an
especially
designed
flap
on
the
right
side
of
the
unit.
-
Access
to
pressure
inlet
for
pressure
switch
connection
is
through
a
specially
designed
liquid
sight
glass
on
the
left
side
of
the
unit.
Following
this
operating
mode
allows
unit
tests
to
be
carried
out
with
the
door
closed,
ensuring
operators’
safety
as
well
as
the
correct
running
of
the
device,
avoiding
air
by-pass
phenomena.
Leaks
testing
Pressurise
the
whole
system,
including
the
condensing
unit,
using
a
neutral
gas
(Nitrogen
R)
with
a
(non-liquid,
non-colouring)
tracer,
at
a
minimum
pressure
of
10
bars
and
at
a
maximum
pressure
of
less
than
20.5
bars,
isolating
the
LP
(low
pressure)
switches.
Important:
If
the
LP
circuit
is
fitted
with
a
safety
valve
(e.g.:
on
the
suction
accumulator)
the
test
pressure
on
that
part
of
the
circuit
should
be
approx.
20%
below
the
operating
pressure
of
this
valve.
Thorough
leakage
detection
using
a
suitable
detector
should
be
carried
out
on
the
condensing
unit.
After
these
tests,
the
gas
must
be
removed.
Fit
the
drier
cartridges
in
their
casing.
Dehydration
of
circuits
This
operation
must
be
carried
out
with
all
valves
open
(including
solenoid
valves)
with
connection
to
a
vacuum
pump:
-
of
the
low
pressure
side
-
of
the
high
pressure
side
The
quality
of
drying
should
not
be
judged
by
the
speed
at
which
the
level
of
vacuum
is
reached
but
on
the
effective
time
it
is
held
(24
hours
at
0.7
mbar
is
a
good
standard).
The
total
increase
in
pressure
during
that
period
should
not
be
more
than
2.6
mbar.
The
residual
moisture
in
the
system
should
be
less
than
20ppm.
When
the
installation
is
under
vacuum,
an
insulation
check
of
the
motor
should
not
be
carried
out
nor
should
the
compressors
be
started
before
at
least
1
bar
of
fluid
pressure
is
reintroduced.
This
is
to
prevent
motor
winding
damage.
Oil
level
checks
After
a
minimum
of
2
hours
of
operation,
check
the
oil
compressor
levels.
The
compressor
oil
level
should
be
between
the
bottom
and
the
top
quarters
of
the
sight
glass.
Oils
The
compressor
Manufacturer's
recommendations
should
be
followed
according
to
the
type
of
refrigerant.
The
use
of
colorants
or
UV
tracers
as
leak
detectors
in
the
oil,
is
not
allowed.
MANEUROP
oil
Refrigerant
160
P
R22
MT/LT
compressor
160
PZ
R404A/
R507/134a
MTZ/LTZ
compressor
This
table
is
not
exhaustive,
but
summarises
the
main
oils
used.
If
any
other
oil
is
to
be
used,
we
would
advise
contacting
PROFROID
or
the
compressor
manufacturers.
Refrigerant
fluid
charge
It
is
possible
to
charge
in
liquid
phase
when
the
installation
is
under
vacuum
through
the
charging
valve
provided
on
the
liquid
receiver
(depending
on
models).
The
charging
bottle
must
remain
connected
to
this
valve
permanently
during
the
whole
start-up
period
to
enable
instant
adjustment
while
charging
the
installation.
