4 Troubleshooting
Analysis and countermeasure of abnormalities
SMGB0120 rev.0 - 11/2017
123
4
Phenomenon
Cause
Check Item
Action · Countermeasure
Chiller unit
stops during
cooling
operation
Discharge
gas over-
increase is
activated
Suction gas temperature is
too high (excessive super
heat)
Malfunction of check valve
Replace check valve
Clogging of expansion valve
Remove clogging
Malfunction of the expansion
valve
Replace expansion valve
Failure of thermistor for
control of discharge gas
Check connection with a tester
Replace thermistor for
control of discharge gas
Activation of
overcurrent
protection
control for
compressor.
Activation of
compressor
internal
thermo
Single phase operation
Check electromagnetic switch
Replace electromagnetic
switch
Excessive Compressor
operating current
Power supply voltage too high
or too low
Set voltage during operation
to rated voltage
Phase unbalance in power
supply voltage
Measure voltage between
each phase, and consult with
the power company
Discharge pressure too high
Investigation to determine
the cause
Single phase operation
Power source fuse blown
Replace power source fuse
Loosening of terminal-type
screws of power source
Retighten screws.
Check rough contact of
electromagnetic contactor of
compressor motor
Replace contact
Faulty compressor bearing
It becomes locked.
Compressor replacement
Insulation failure of
compressor motor
Measure insulation resistance
Activation of
overcurrent
relay for
pump
Pump locked
Check frozen water, clogging
by foreign bodies, etc.
Remove
Inappropriate RC value of
overcurrent relay for pump
Check RC value and pump
operating current
Change RC value or replace
electromagnetic switch
Faulty overcurrent relay for
pump
Press reset button.
Check running current
Replace electromagnetic
switch
Activation of
anti-freezing
thermo
Insufficient volume of water
Check cold water inlet/outlet
temperature difference
Increase volume of water.
Pump inverse rotation
Check rotational direction
Fix to correct direction.
Thermistor abnormality
Check cold water inlet temp
Replace Thermistor
Faulty frost-proof thermostat
Check cold water outlet temp
Replace frost-proof
thermostat
Chiller unit
stops during
heating
operation
Activation
of high
pressure
switch
due to
excessively
high
discharge
pressure
Insufficient volume of water
Check hot water inlet/outlet
temperature difference
Increase volume of water
Pump inverse rotation
Check rotational direction
Fix to correct direction
Hot water temp too high
Check thermistor activation
Replace Thermistor
Refrigerant overcharge
Measure cycle temperature
Charge correct volume
