J&E Hall V3 FUSION Technical Manual page 28

FAULT
Compressor internal
overload tripped
Control fuse blown in panel
Starting kit faulty (single
phase units only)
Motor windings faulty
Compressor seized
Mechanical failure
Compressor runs
but no effect on
suction/discharge
(For three-phase scroll
pressures
compressors only)
Operating on safety
switches
Refrigerant levels
Compressor starts
and stops too
quickly
Faulty contactor (if fitted)
Loose / broken wiring
connection
Vibration
Lack of oil
Too much oil
Liquid refrigerant
Compressor is
noisy
Overloaded
High discharge pressure
Internal wear / damage
System load too high
High discharge pressure
Compressor body
too hot
Lack of compressor cooling
Issue: 01.06.2023
POSSIBLE CAUSE
Is the correct voltage at
compressor terminals?
Check relay operation and
contacts and inspect start/run
capacitors
Check resistances of windings
against manufacturer values
Does compressor attempt to start
but does not run correctly (makes
humming sound)? Are amps
equivalent to LRC rating?
Are compressor motor amps lower
than expected? If so - potentially
valve reeds damaged or other
internal wear/damage
The compressor may be running
backwards - the compressor will
also be noisier than normal
Check LP & HP settings - is the LP
differential too small or the HP
setting too low?
Is there too little refrigerant in the
system causing rapid LP tripping
or too much refrigerant in the
system causing HP tripping?
Are the contacts chattering on the
contactor?
Rubber feet mountings worn or
bolts are loose/missing
Check oil sight glass to see if level
below recommended level
Check oil sight glass to see if level
above recommended level
Does compressor 'knock' when
starting up or running? Liquid
refrigerant may be present in oil
and compression chambers
Are suction and discharge
pressures too high? There may be
too much load on the compressor.
Blocked condenser / faulty
condenser fan
Refrigerant overcharge
Non-condensibles in system
Noise is always present even if all
operating conditions are OK?
Are suction and discharge
pressures high?
Blocked condenser / faulty
condenser fan
Suction superheat too high
CHECK
Compressor has overheated -
allow time for reset (up to 3 hours)
and rectify cause
Replace fuse and test - rectify
fault
Replace as necessary
Windings that show open circuit
could be due to internal overload
trip. Wait for reset and recheck. If
continually open circuit - motor
faulty. Replace compressor.
If all electrical checks on
components as above are OK -
Change compressor
Try pump test on compressor. If test
fails - replace compressor.
Swap any two of the incoming
phases to the isolator switch and
recheck.
Check and adjust switch settings.
Check all valves are in open
position
Check refrigerant level and adjust
accordingly
Contacts may be dirty or worn.
Check and replace contactor as
necessary
Make sure all electrical connections
are sound
Replace mountings and
tighten/replace bolts as necessary
Top up with oil as necessary
Remove oil overcharge
Identify cause of liquid return to
compressor and rectify
Identify cause of increased load
and rectify
Check and rectify
Check and rectify
Reclaim refrigerant, evacuate &
recharge
Replace compressor
Reduce load at evaporator
Check and rectify
Check refrigerant charge correct
Check TEV superheat setting
correct
Is suction line correctly insulated?
SOLUTION
Page 25