4 Troubleshooting
Analysis and countermeasure of abnormalities
SMGB0120 rev.0 - 11/2017
122
Phenomenon
Cause
Check Item
Action · Countermeasure
Pump is
operating, but
compressor is
not operating.
Faulty PCB
Bad connection of wiring
Check connection with a
tester
Correct wiring connection
Faulty PCB
Check connection with a
tester
Check PCB with self-
diagnosis
Replace PCB
Failure of remote control switch
Operation is possible by
activation from the main
unit side
Replace remote control
switch
Pump.
Compressor is
not operating
Faulty PCB
Bad connection of wiring
Check connection with a
tester
Correct wiring connection
Faulty PCB
Defective thermistor
Measure resistance of
thermistor
Replace thermistor
Faulty
electromagnetic
contactor of
compressor
Disconnection of coil
Check connection with a
tester
Replace electromagnetic
contactor
Bad connection of contact
Voltage measurement
between contacts of
electromagnetic contactor
Thermostat is operating
Try to turn the knob of the
thermostat, in order to
change the temperature.
This is not a failure.
Faulty compressor motor
Measure resistance between
wires
Compressor replacement
Faulty compressor
Howling sounds originating
from compressor
Chiller Unit
stops during
Cooling
operation
Low voltage at startup.
Voltage measurement
Consult with the power
company
Activation of
high pressure
switch due to
excessively
high discharge
pressure
Refrigerant overcharge
Check cycle temperature
Charge correct volume
Mixture of non-condensable
gas in refrigerant cycle
Stop the chiller unit and
check the relation between
water temperature and
pressure
Recharge refrigerant after
vacuum pumping
Clogging of discharge pipes
Check for clogging
Check for clogging
Clogging of expansion valve
Clogging of check valve
Remove clogging, or
replace check valve
Clogging of strainer
Check difference of
temperature before and after
the strainer
Replace or wash the
strainer
High temperature of the cold
(hot) water inlet at the heat
exchanger
Check whether the usage
range is being exceeded
Investigate the situation
of heat load well and take
action
Thermostat
for discharge
gas overheat
prevention is
activated
Suction gas temperature is
too high.
(Excessive super heat)
Gas leakage or insufficient
refrigerant
Charge correct refrigerant
volume after checking gas
leakage
Malfunction of the expansion
valve
Replace expansion valve