J&M CellarPlus 70-S1/S3, Technical Manual

Page: 17 / 32

Issue: 01.06.2023 Page 14
FAULT POSSIBLE CAUSE CHECK SOLUTION
Loose / broken wiring
connection Make sure all electrical connections are
sound
Compressor is
noisy Vibration Rubber feet mountings worn or
bolts are loose/missing Replace mountings and tighten/replace
bolts as necessary
Liquid refrigerant Does compressor 'knock' when
starting up or running? Liquid
refrigerant may be present in
oil and compression chambers Identify cause of liquid return to
compressor and rectify
Overloaded Are suction and discharge
pressures too high? There may
be too much load on the
compressor. Identify cause of increased load and
rectify
High discharge pressure Blocked condenser / faulty
condenser fan Check and rectify
Refrigerant overcharge Check and rectify
Non-condensable in system Reclaim refrigerant, evacuate &
recharge
Internal wear / damage Noise is always present even if
all operating conditions are
OK? Replace compressor
Compressor
body too hot System load too high Are suction and discharge
pressures high? Reduce load at evaporator
High discharge pressure Blocked condenser / faulty
condenser fan / airflow around
unit restricted Check and rectify
Lack of compressor
cooling Suction superheat too high Check refrigerant charge is correct
Too much heat load at evaporator -
reduce
Are refrigerant lines correctly
insulated?
Compressor starting too
frequently Refer section above '
Compressor starts and stops
too quickly' Refer section above ' Compressor starts
and stops too quickly'
Discharge gas bleeding
into suction side Does suction pressure rise
abnormally quickly when
compressor stops Compressor valves may be damaged -
replace compressor
CONDENSER FAN
Condenser fan
not running Power supply See compressor will not start
section See compressor will not start section
Compressor contactor not
pulled in See compressor will not start
section See compressor will not start section
Compressor contactor
pulled in Is voltage being switched
across contactor? (Terminals L1
& T1) If yes - check voltage to fan motor. If
correct voltage present at motor - fan
faulty. Replace fan motor
If no. Replace faulty contactor
Fan being controlled by
Fan Speed Controller (if
fitted) Is system operating pressure
below FSC setting? If yes - all OK (check fan operates
when pressure rises)
Fan capacitor fault Check visual condition of
capacitor and check uF reading
with capacitor meter. Replace capacitor as required
Motor fault If FSC fitted - bypass FSC to
test motor. If motor still does
not run - motor is faulty Replace fan motor
Condenser fan
runs but only
slowly Fan capacitor or motor
fault See above See above
Is fan being controlled
by a FSC? Adjust FSC setting - does fan
speed up? If yes - all OK
FSC faulty If fan runs slowly even after
adjusting FSC with head
pressure rising - FSC may be
faulty Replace FSC
INDOOR UNIT
Power supply Is power switched on? If not - switch on