Table 27 Table; Table 23 Compressor And Refrigeration System Troubleshooting - Emerson Liebert Deluxe System/3 DE Operation And Maintenance Manual

Table 23 Compressor and refrigeration system troubleshooting
Symptom
Compressor will not
start
Compressor will not
operate, contactor not
pulling in
Compressor will not
operate, contact not
pulling in
Compressor contactor
pulled in but
compressor will not
operate
Compressor runs for
three minutes then
stops; contactor drops
out. Motor operates but
valve won't open
High discharge
pressure
Low discharge pressure
Low suction pressure
Possible Cause
Power off
Current overload open
Loose electrical connections
Compressor motor burned out
No call for cooling
Solenoid valve not energizing
Low pressure switch not making
contact
High pressure switch open
Blown fuse or tripped CB
Low pressure switch not closing
Solenoid not opening
Dirty condenser or drycooler fins
Condenser equipment not
operating
High refrigerant charge
Hot gas bypass valve adjusted
improperly
Water regulating valve adjusted
improperly
Excessive water now through
condenser
Suction service valve partially
closed
Leaky compressor suction valves
Worn piston rings
Faulty head pressure control
valve or condenser fan speed
control
Insufficient refrigerant in system
Dirty air filters
Plugged filter-drier
Improper superheat adjustment
Defective expansion valve
sensing element
Poor air distribution
Low condensing pressure
Slipping belts
Check or Remedy
Check main switch, fuses or CBs and wiring
Reset manually
Tighten connections
Check and replace compressor if defective.
Check monitor status.
Hold screwdriver over solenoid and check for magnetic field.
This indicates solenoid is energized.
Check gas pressure - manually energize low pressure
switch.
Reset switch. Refer to other refrigeration troubleshooting
suggestions.
Check for line voltage after fuses or CBs, and after
contactors.
Check for low gas pressure. Compressor is running on
Positive Start Kit (air cooled systems only).
Check magnetic field to see if energized.
Clean coil
Check operation.
Check refrigerant charge.
Adjust properly.
Adjust properly.
Adjust water regulating valve
Open the valve.
Pump down, remove the cylinder head, examine valves and
valve seats; replace if necessary
Replace compressor.
Replace if defective.
Check for leaks, repair, and add refrigerant
Change filters.
Replace filter.
Reset expansion valve for 10-15°F
Replace element
Check duct work for closed dampers. Check for underfloor
restrictions at or near the unit.
Check head pressure control device.
Inspect and adjust
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Troubleshooting