Specifications
SLOW
LEAK IN
SYSTEM
On forced air
models, long run time will
be
noticed during the
early
stages of a
leak. As the refrigerant
continues
to es-
cape, both compartments
will
gradually
warm up and the compressor will run
continuously.
The freezer will
probably
warm
up
first.
INCORRECT REFRIGERANT
CHARGE
The
sealed unit
may
have too much refri-
gerant
(overcharged
system) or too little
refrigerant
(undercharged
system). The
following
paragraphs
will inform
you
on
how to recognize
a
system
with these
de-
fects.
An
overcharged system may
have a frost
back condition
appearing outside the
in-
sulation
sleeve on the
suction line
at
the
cabinet
rear.
When the
compressor
stops,
the frost
melts
and drips on the floor.
A
heat
exchanger
separation will
also cause
this
symptom.
An
undercharged
system depending
on
the
degree
of undercharge,
will
operate
with temperatures
above normal
and the
compressor
run time
will be increased.
The
greater
the
undercharge,
the higher
the temperature
will
be
and
the longer
the
run
time.
An
undercharged
system must
be
purged,
evacuated,
and recharged
with the
proper
amount
of refrigerant.
Before recharging,
however,
test for
refrigerant leaks.
DEFECTIVE
COMPRESSOR
A
compressor which is not
pumping
ade-
quately
will not
cool effectively.
All cool-
ing
surfaces
may be covered
with a thin
film
of
frost,
but the
temperature will
not
descend to the
cut-out temperature
of the
control, even
with continuous
running
of
the
compressor.
Because these
symptoms
are similar to
a
refrigerant leak, it
is
advisable to thor-
oughly leak
test
at
this
point.
lf no leak
is
indicated,
install
gauges
and check the
operating
pressures.
lf the
high side
pres-
sures are lower
than those
specified,
and
low side
pressures
are higher than
speci-
fied,
suspicions of
an inefficient
compres-
sor will
be confirmed
and the compressor
must be replaced.
PRESSURE
UNLOADING IN
SYSTEM
The
compressor may
stall
and cycle on
the
overload
protector
if
an attempt is
made
to restart the
unit immediately
after
it has
stopped. This
is
because
the refri-
gerant
pressure
is
high
on the condenser
side and low on the
evaporator
side. When
the
compressor
stops running, the liquid
slowly
passes
through
the capillary tube
and the
pressures
are said to be
"unload-
ing". Pressure
unloading in the system
may
take from
3
to
6 minutes.
PULL
DOWN
OVERLOAD
lf the
cabinet
compartments
are
warm
when
the
compressor starts, the
"pull
down" may
temporarily
overheat the
compressor
and cause
cycling on the ov-
erload
protector.
3-6