Table 15 Compressor And Refrigeration System Troubleshooting - Emerson Liebert Challenger iCOM 3000 Operation & Maintenance Manual

Table 15 Compressor and refrigeration system troubleshooting
Symptom
Power Off
Current overload open
Compressor will not
start
Loose electrical connections
Compressor motor burned
out
No call for cooling
Solenoid valve not
Compressor will not energizing
operate, contactor
not pulling in
Compressor will not
operate, contact High pressure switch open
not pulling in
Compressor
contactor pulled in
Blown fuse or tripped CB
but compressor will
not operate
Inadequate suction
Compressor runs
pressure- Low Pressure
for three minutes
alarm
then stops;
contactor drops
Liquid line solenoid valve not
out.
opening
Dirty condenser or drycooler
fins
Condenser equipment not
operating
High discharge
High refrigerant charge
pressure
Hot gas bypass valve
adjusted improperly
Water regulating valve
adjusted improperly
Excessive fluid flow through
condenser
Suction service valve
partially closed
Low discharge
Faulty head pressure control
pressure
valve or condenser fan
speed control
Compressor rotation in
reverse direction
Insufficient refrigerant in
system
Dirty air filters
Plugged filter-drier
Improper superheat
adjustment
Low suction
pressure
Defective expansion valve
sensing element
Poor air distribution
Low condensing pressure
Slipping belts
Possible Cause
Check main switch, fuses or CBs and wiring
Re-set units with overload option manually. Allow compressor to cool
for internal overloads to reset.
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.
Get the unit in a call for cooling or place the compressor into charge
mode through the Diagnostics / Service Mode (see SL-18835). Check
control voltage across the compressor contractor coil. Check freeze
stat continuity as needed.
Reset switch. Refer to other refrigeration troubleshooting
suggestions.
Check for line voltage after fuses or CBs, and after contactors.
iCOM has built in positive start kit (see Low-Pressure Time Delay in
SL-18835).
Check magnetic field to see if energized.
Clean coil.
Check operation.
Check refrigerant charge.
Adjust properly.
Adjust properly.
Adjust fluid regulating valve
Open the valve.
Replace if defective.
Check for proper power phase wiring to unit and to compressor
motor.
Check for leaks, repair, and add refrigerant for air-cooled. Evacuate
and recharge for water/glycol unit.
Change filters.
Replace filter.
Reset expansion valve for 10-15
(6-8°C)
Replace element
Check duct work for closed dampers. Check for under-floor
restrictions at or near the unit.
Check head pressure control device.
Inspect and adjust
Check or Remedy
°
33
Troubleshooting
F
Liebert ® Challenger 3000
™