32/61
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TROUBLESHOOTING
Examples
of
faults
and
solutions
FAULT
PROBABLE
CAUSE
ACTION
REQUIRED
1.
Suction
Temperature
too
high
Too
much
suction
gas
superheat
Examine
and
adjust
the
thermostatic
expansion
valves
in
the
evaporators.
2.
Suction
Temperature
too
low
Liquid
in
the
suction
line.
Adjust
thermostatic
expansion
valves.
Sensor
bulb
is
loose
or
incorrectly
positioned.
Check
if
the
bulb
is
in
contact
with
the
suction
line
and
if
it
is
positioned
correctly
3.
Suction
Pressure
too
low
Too
much
oil
in
evaporators.
Drain
oil
from
evaporators.
Filter
in
the
liquid
line
clogged.
Examine
and
clean
filters
in
liquid
line.
Suction
filter
blocked.
Check
intake
filter.
Too
much
superheat
of
suction
gas.
Adjust
thermostatic
expansion
valves.
Thermostatic
expansion
valve
blocked
when
in
closed
position.
De-ice
thermostatic
expansion
valve
using
warm
rags.
If
no
improvement,
change
the
thermostatic
expansion
valve.
Problem
with
solenoid
valve
in
the
liquid
line.
Check
wiring
and
coil
–
replace
if
necessary
Installation
insufficiently
charged.
Charge
the
installation
with
refrigerant.
4.
Compressor
cuts
in
and
out
too
often
on
LP
safety
switch
See
point
3
Low
pressure
safety
switch
set
too
high.
Adjust
pressure
safety
switch.
Evaporator
iced
over
or
frozen
water
present
in
the
distributor.
Clean
or
defrost
evaporator.
5.
Suction
Pressure
too
high
Restart
after
defrost.
Wait
for
confirmation
Compression
problems
Check
valves
and
gaskets
6.
Condenser
Pressure
too
high
Insufficient
flow
of
air
in
to
the
condenser
Clean
the
condenser.
Check
motor
fans
Fan
cut
in
not
adjusted
correctly
Adjust
High
pressure
safety
valve
set
too
low
Set
pressure
valve
at
maximum
1
bar
below
Maximum
Safe
Pressure,
but
take
into
account
the
compressor
limit.
Installation
flooded
Drain
liquid
into
reservoir
Air
or
non-condensable
gas
in
the
HP
circuit
Let
air
out
at
highest
point.
7.
Condenser
pressure
too
low
Fan
cut-in
incorrectly
set.
Adjust
pressure
switch
8.
Discharge
Temperature
too
high
Too
much
superheat
on
suction.
Adjust
thermostatic
expansion
valves.
Internal
by-pass.
Check
valves
and
joints.
9.
Oil
temperature
too
high
Superheat
on
suction
too
great.
Check
and
adjust
thermostatic
expansion
valves
Valve
problems.
Check
pressures.
If
necessary,
adjust
valves
and
gaskets.
10.
Oil
temperature
too
low
Crankcase
heater
out
of
order.
Replace
heater
Oil
return
saturated
in
liquid
refrigerant
Adjust
thermostatic
expansion
valve
11.
Capacity
too
great
Problem
with
control
system
or
other
automatic
devices.
Replace,
repair
or
re-set
12.
Insufficient
Capacity
Problem
with
control
system
or
other
automatic
devices
Replace,
repair
or
re-set.
13.
Oil
foams
heavily
after
stoppage
Thermostatic
expansion
valve
(fluid
in
suction
line).
Check
thermostatic
expansion
valve.
Bulb
loose
or
incorrectly
positioned
Check
bulb
position
Crankcase
heater
out
of
order
Replace
heater
