TROUBLESHOOTING CHART
COMPRESSOR WILL
NOT RUN
COMPRESSOR
NOISY
OR VIBRATING
HIGH DISCHARGE
PRESSURE
LOW DISCHARGE
PRESSURE
HIGH SUCTION
PRESSURE
LOW SUCTION
PRESSURE
COMPRESSOR WILL
WILL NOT UNLOAD
OR LOAD
COMPRESSOR
LOADING/UNLOADING
INTERVALS
TOO SHORT
LOSS OF OIL
PRESSURE OR
NUISANCE OIL
PRESSURECONTROL
TRIPS
COMPRESSOR
LOSES OIL
6.
7.
6.
9.
Main switch open.
Fuse blown. Circuit breakers open.
Thermal overloads tripped.
Defectve
contactor or coil.
System shut down by safety
devices
No cooling required.
Liquid line solenoid will not open.
Motor electrical trouble.
Loose wiring
1.
Flooding
of refrigerant into crankcase
2. Improper
piping
support on suction or
liquid
line
3. Worn compressor.
1. Noncondensables in system.
2. System overcharged with refrigerant.
3. Discharge shutoff valve partially closed.
4. Fan not
running.
5. Dirty condenser
coil
6. FANTROL out of adjustment.
1. Check
setting
of
expansion
valve.
2.
Relocate, add or remove hangers
3.
Replace.
1.
Purge the noncondensables.
2.
Remove excess.
3.
Open valve.
4. Check electrical circuit.
5.
Clean coil.
6.
Adjust
FANTROL settinqs.
1.
Faulty condenser temperature regulation.
2. Suction shutoff valve partially closed
3. Insufficient refrigerant in system.
4. Low suction pressure.
5. Compressor operating unloaded
1.
Check condenser control operation.
2. Open valve.
3. Check for leaks.
Rapair
and add charge.
4. See Corrective Steps for low suction pressure
5. See Corrective Steps for failure of compressor
below.
1.
Excessive load.
1. Reduce load or add
additional
equipment.
2. Expansion valve
overfeeding.
2. Check remote bulb. Regulate superheat.
3. Compressor unloaders open
3. See
Corrective
Steps below for failure of
comp
1. Lack of
refrigerant
2. Evaporator dirty.
3. Clogged liquid line filter-drier
4. Clogged suction line or compressor suction gas s
5. Expansion valve
malfunctioning.
6. Condensing temperature too low.
7. Compressor will not load.
8. Insufficient
air
or water flow. 8. Adjust
airflow
or water
gpm.
1. Defective capacity control.
1
Replace.
2. Unloader mechanism defective.
2.
Replace.
3. Faulty thermostat stage or broken capillary tube.
3.
Replace.
4. Staaes not set for application. 4. Reset thermostat setting to fit
application.
1.
Erratic water thermostat.
1
Replace.
2. Insufficient water flow
2
Adjust
gpm
1. Clogged suction oil strainer
2. Excessive
liquid
in crankcase.
3. Oil pressure gauge defective
6. Oil pump reversing gear stuck
in
wrong position.
4. Low oil pressure safety switch defective.
5. Worn oil pump.
7. Worn bearings.
8. Low oil level.
6 Reverse direction of compressor rotation.
7. Replace compressor.
3 Repair or replace. Keep valve closed except
w
6. Add
oil.
readings.
4 Replace.
5. Replace
9. Loose fitting on oil lines.
10. Pump housing gasket leaks.
11.
Flooding of refrigerant into crankcase.
12. Iced up evaporator coil.
13. Insufficient air or water flow.
9. Check and
tighten
system.
10. Replace gasket.
11.
Adjust thermal expansion valve.
12 Clean coil.
13. Adjust air flow or water qpm.
1.
Lack of refrigerant.
1. Check for leaks and repair Add refrigerant.
2. Excessive compression ring blow-by
2. Replace compressor.
3. Suction superheat too high 3. Adjust superheat.
4. Crankcase heater burned out. 4. Replace crankcase heater.
5. Insufficient oil in system. 5. Add
oil
until sightglass IS
l/3
full.
6. Suction risers too large 6. Check line sizing at
design
conditions and
cha
7. Insufficient traps in suction
risers.
6.
7.
8.
9.
Close switch.
Check electrical circuits and motor winding for
grounds Investigate for possible overloading.
fuse or reset breakers after fault is corrected.
loose or corroded connections.
Overloads are auto reset. Check
unit
closely
w
comes back on line.
Repair
or replace.
Determine
type and cause of shutdown and cc
before resetting safety
switch.
None. Wait until unit calls for cooling
Repair
or replace coil.
Check motor for opens, short circuit, or
burno
Check all
wire
junctions. Tighten all terminal s
shorts or
Replace
Check for
hen
unit
rrect
it
ut
crews.
below.
to load
load.
1. Check for leaks.
Repair
and add charge
2. Clean
chemically.
3. Replace.
4 Clean strainers.
5. Check and reset for proper superheat.
6. Check means for regulating condensing tempe
7. See Corrective Steps below for failure of
comp
unload.
ressor
to
rature.
ressor
to
1.
Clean.
2. Check crankcase heater. Reset expansion val
higher superheat. Check liquid line solenoid vi
operation.
ve
for
alve
hen taking
incorrect.
7.
Install suction P-traps at each 20 foot vertical
nge if
rise.
Continued
on
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IM
269
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