Diagnosis
152
Condition
Possible Cause
Remedy
Compressor contactor
burned out
Low line voltage
Increase line voltage to at least 90% of
compressor motor rating
Excessive line voltage
Reduce line voltage to at least 110% 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, water
pressure switch (option), water flow rate
(option) and \water-cooled
condenser-receiver tank (optional)
Noisy unit
Insufficient compressor oil
Add oil to proper level
Loose mounting bolts
Tighten mounting bolts
Oil slugging or refrigerant flooding
back
Add oil or refrigerant charge. Check
expansion valve adjustment
Worn fan motor bearings
Replace bearings or motor
Faulty compressor
Repair or replace compressor
Condenser fan motor does
not operate
Unit in Heat or Defrost
Check indicator lights. If unit is in Heat or
Defrost, unit operation is normal (no
remedy required)
Unit in Cool with Low condenser
temperature
Check indicator lights, 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)
Condenser Fan switch OFF
(Water-cooled position) (Option)
If unit is on water cooled condenser
operation, unit operation is normal.
Otherwise Condenser Fan On/Off switch
position must be ON for air-cooled
condenser operation.
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
Defective condenser fan contactor
Replace defective contactor
No condenser fan output signal from
controller
Diagnose and replace condenser fan
relay, main relay board, or controller
Summary of Contents for CRR-40 119
Page 4: ......
Page 16: ...Safety Precautions 16...
Page 18: ...Service Guide 18...
Page 20: ...Model Features 20...
Page 32: ...Specifications 32...
Page 120: ...MP 3000a Controller 120...
Page 160: ...Wiring and Schematic Diagrams Index 160...
Page 161: ...161 MPC2000 Wiring Schematic...
Page 162: ...162 MPC2000 High Voltage Wiring Diagram...
Page 163: ...163 MPC2000 Low Voltage Wiring Diagram...
Page 164: ...164 MPC2000 WCC Wiring Schematic...