| Compressor does not operate - no amperage draw. |
Controller on; unit start sequence still timing. |
Wait up to two minutes for compressor start-up. |
| No power to unit (condenser and evaporator fans do not operate). |
Locate fault
and repair: power source, power plug, CB1 main circuit breaker, motor
contactors, motor terminals, motor. |
| Open in 29 Vac control circuit. |
Check fuses and On/Off switch. Replace or repair as required. |
| Container temperature does not demand compressor operation. |
Adjust controller setpoint. |
| Compressor contactor inoperative. |
Replace compressor contactor. |
| No output signal from controller. |
Diagnose and replace the controller. |
| Unit on defrost. |
Turn Unit On/Off switch Off and then On again. |
| Detective high pressure or low pressure cutout switch. |
Replace defective switch. |
| High condenser head pressure causing high pressure cutout. |
Check refrigeration system and correct fault. |
| Defective compressor. |
Replace compressor. |
| Controller shut unit down on Compressor Over Temperature. |
Let compressor cool and controller will reset automatically.
Check vapor injection valve and compressor temperature sensor. |
| Compressor motor internal thermal overload protection open. |
If compressor contactor is energized, wait 60 minutes for protector
to cool and reset. |
| Compressor does not operate - excessive amperage
draw or intermittent cycling on overload. |
Rotating scroll stuck. |
Replace compressor. |
| Seized or frozen compressor bearings. |
Replace compressor. |
| Improperly wired. |
Check/correct wiring against wiring diagram. |
| Low line voltage. |
Check line voltage - determine location of voltage drop. |
| Contacts in compressor contactor not closing completely. |
Check by operating manually. Repair or replace. |
| Open circuit in compressor motor winding. |
Check motor stator connections. Check stator winding for continuity.
If open, replace compressor. |
| Defective compressor motor internal thermal overload protector. |
Replace thermal overload protector or compressor. |
| Refrigerant overcharge or high side restriction causing cycling
on high pressure cutout. |
Check for restricted filter drier, in-line filter or high side;
or refrigerant overcharge. |
| Inefficient condenser operation causing cycling on high pressure
cutout. |
Check condenser airflow, condenser fan motor, fan blade, condenser
grille, condenser coil temperature sensor, water pressure switch (option),
water flow rate (option) and water-cooled condenser-receiver tank
(option). |
| Compressor contactor burned out. |
Low line voltage. |
Increase line voltage to at least 90 percent of compressor
motor rating. |
| Excessive line voltage. |
Reduce line voltage to at least 110 percent of compressor motor
rating. |
| Short cycling. |
Eliminate cause of short cycling. |
| Unit short cycles. |
Refrigerant overcharge causing cycling on high pressure cutout. |
Purge system. |
| Inefficient condenser operation causing cycling on high pressure
cutout. |
Check condenser airflow, condenser fan motor, condenser fan
grille, condenser fan pressure switch, water pressure switch (option),
water flow rate (option) and water-cooled condenser-receiver tank
(option). |
| Noisy compressor |
Loose mounting bolts. |
Tighten mounting bolts. |
| Oil slugging or refrigerant flooding back. |
Perform controller pretrip test to check refrigerant charge.
Check expansion valve adjustment. Check compressor for compressor
oil. |
| Scroll rotating backwards. |
Check phase correction system and check unit wiring. |
| Defective compressor. |
Repair or replace compressor. |
| Condenser fan motor does not operate. |
Unit in Heat or Defrost. |
Check indicator. If unit is in Heat or Defrost, unit operation
is normal (no remedy required). |
| Unit in Cool with low condenser temperature. |
Check indicator condenser temperature and discharge pressure.
Condenser temperature may not require condenser fan operation (no
remedy required; condenser fan also pulses on and off on a 30 second
cycle to control condenser temperature). |
| Water pressure switch closed (Water-cooled position) (Option). |
If unit is on water cooled condenser operation, unit operation
is normal. Otherwise water pressure switch must be Open for air-cooled
condenser operation. |
| Defective water pressure switch (option). |
Replace defective switch. |
| Loose line connection. |
Tighten connections. |
| Open motor internal thermal overload protector. |
Check for seized bearings or defective thermal overload protector.
Repair or replace as necessary. |
| Defective motor. |
Replace motor. |
| Detective condenser fan contactor. |
Replace defective contactor |
| No condenser fan output signal from controller. |
Diagnose and
replace condenser fan contactor or controller. |
| Evaporator fan motor(s) does not operate. |
Unit on defrost. |
Check operating mode indicator LEDs. |
| Loose line connection. |
Tighten connections. |
| Open motor internal thermal overload protector. |
Check for seized bearings or defective thermal overload protector.
Repair or replace as necessary. |
| Defective motor. |
Replace motor. |
| No low or high speed evaporator fan output signal from controller
output module. |
Diagnose and replace output module or controller. |
