59/61
The
defrost
thermostats
or
limiters
must
be
set
at
the
threshold
of
the
ambient
air
temperature.
Any
water
drain
pipes
must
be
fitted
with
drain
line
heaters.
Water
defrost
Some
CRW
units
are
fitted
with
a
liquid
defrost
ramp.
In
this
case,
a
solenoid
valve
with
a
filter
and
a
flow
valve
must
be
provided
outside
the
room.
The
flow
valve
controls
the
flow
of
water
and
prevents
water
from
overflowing
out
of
the
defrost
tray
and
splashing,
particularly
into
motors.
A
diameter
at
least
equal
to
80mm
should
be
provided
for
water
drainage
pipes..
Electrical
protection
For
electrical
motors,
this
must
conform
to
standards
in
force
and
must
be
set
according
to
the
maximum
current
for
the
speed
used.
For
electric
heaters,
the
protection
is
linked
to
the
neutral
circuit:
-
Neutral
TT
:
Differential
circuit
breaker
300
mA.
-
Neutral
IT
:
Fuses.
-
Neutral
TN:
We
advise
the
installation
of
a
differential
circuit
breaker
300
mA.
Where
the
neutral
is
distributed,
heaters
are
connected
at
the
star
point.
(Note:
on
some
industrial
models,
neutral
is
located
on
the
opposite
side
of
the
cooler).
-
START-UP
OPERATIONS
PRELIMINARY
CHECKS
Ensure
that
all
the
threads
are
fully
tightened
on
fans
(jolting
during
transportation
could
cause
them
to
loosen).
Check
also
if
there
are
any
breaks
in
the
piping.
(breaks
could
occur
during
transportation).
LEAKAGE
TESTING
Pressurise
the
whole
system,
including
the
cooler,
using
a
neutral
gas
(Nitrogen)
with
a
(non-liquid,
non-colorant)
tracer
at
a
minimum
pressure
of
10
bars
and
at
a
maximum
pressure
below
20.5
bars,
isolating
the
LP
(low
pressure)
switches.
Important:
If
the
LP
(low
pressure)
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
unit.
DEHYDRATION
OF
CIRCUITS
This
operation
must
be
carried
out
with
all
valves
open
(including
solenoid
valves)
with
connection
to
a
vacuum
pump
of
the
HP
and
LP
sides.
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.
(To
prevent
motor
windings
damage).
FAN
CHECKS
Check
that
the
fans
are
rotating
in
the
correct
direction,
i.e.
drawing
on
the
coil
except
BP/BN
blowing
through
the
coil.
Measure
the
current
absorbed
by
each
motor
and
compare
with
the
nominal
current
(displayed),
taking
into
account
the
network
current.
HEATER
CHECKS
Check
heating
Ensure
that
the
currents
passing
through
the
three
phases
are
identical
and
that
there
has
not
been
an
imbalance
in
the
circuit.
If
so,
re-balance
the
circuit
or
replace
the
non-working
heaters.
Heater
insulation
Allow
the
heaters
to
warm
up.
Cut
off
supply
to
these
and
very
quickly
take
the
insulation
value
on
the
heater
contactor
between
the
phase
and
earth.
If
this
is
over
3K
ohms
when
hot,
it
is
satisfactory.
If
not,
check
where
the
breakdown
of
insulation
is,
or
for
deficient
heaters.