30/61
Discharge
pressure
Measure
suction
temperature
Measure
discharge
temperature
Measure
crankcase
temperature
acting
at
the
oil
drain
plug.
-
The
intake
superheat
must
not
exceed
18K
and
should
not
fall
below
10K
for
medium
temperature
and
11K
maxi
for
low
temperature.
Therefore
adjust
the
thermostatic
expansion
valve
and
ensure
that
the
charge
in
the
condensing
unit
is
correct.
-
The
discharge
temperatures
on
the
high
pressure
line
must
be
within
the
following
range:
.
R404
70°C
<
T°
discharge
<
100°C
-
The
crankcase
temperature
must
not
fall
below
40°/45°C
Very important:
There
is
no
need
to
add
oil
over
and
above
the
required
quantity
during
start-up.
Wait
several
hours.
Excess
oil
generally
leads
to
oil
slugs
on
the
condensing
unit
which
causes
damage
to
the
compressors
(broken
valves
or
gaskets).
If
oil
level
is
low,
this
could
be
caused
by:
-
Too
much
oil
being
entrained
by
emulsification
in
the
crankcases
resulting
in
an
excessive
amount
of
refrigerant
fluid
being
dissolved
into
the
oil
(superheat
too
low
at
suction
inlet
-
crankcase
heaters
defective
or
not
energised).
-
Bad
design
of
the
LP
piping
on
the
equipment
trapping
the
oil,
particularly
when
running
with
reduced
refrigerant
charge.
Fans
Check
the
current
absorbed
from
the
motors.
-
MAINTENANCE
OPERATING
INSTRUCTIONS
FOR
MAINTENANCE
For
all
maintenance
operations,
the
following
instructions
must
be
followed:
-
Unit
doors
must
only
be
opened
after
the
main
switch
has
been
cut-off
and
the
fans
have
stopped
completely.
-
HP
and
LP
pressure
switches
can
be
accessed
with
the
door
closed
through
a
specially
designed
flap
on
the
right
side
of
the
unit.
-
The
pressure
inlet
for
pressure
switch
connection
can
be
accessed
through
the
specially
designed
liquid
sight
glass
flap
on
the
left
side
of
the
unit.
Following
these
instructions
allows
unit
tests
to
be
carried
out
with
the
door
closed
while
ensuring
operators’
safety
as
well
as
the
correct
running
of
the
device
avoiding
any
air
by-pass
phenomenon.
RECOMMENDATIONS
If
the
unit
is
stopped
for
long
periods
of
time,
the
fan
motors
should
be
run
for
at
least
two
hours
each
week.
.
Every
month:
Carry
out
an
operating
check
on:
-
Pressures
and
temperatures
in
the
compressor
-
Voltages
in
compressors
and
fan
motors
-
Safety
cut-off
points
of
HP/LP
safety
pressure
switches.
-
Cut-in
of
safety
pressure
switches
in
condenser
fans,
-
Oil
levels
-
Moisture
in
the
circuits
(through
sight-glass
or
by
analysing
oil)
-
Check
for
leaks
in
the
refrigeration
circuit
-
Cleanliness
of
coil
-
Position
of
rotors
in
ferrules
(
tightness
on
shaft,
state
of
blades,
...).
.Every
year:
-
Carry
out
analysis
of
oil
-
Clean
the
condenser.
-
In
the
case
of
HFC
type
fluid
(
R404A
),
activated
aluminium
oxide
driers
should
be
avoided,
driers
with
a
molecular
filter
should
be
chosen
instead.
Instructions
or
recommendations
appearing
in
the
various
technical
advice
notes
and
manufacturer's
service
manuals
should
be
followed
precisely;
please
contact
our
Technical
Department
for
any
additional
information
CLEANING
Coils
should
preferably
be
cleaned
with:
