4. Troubleshooting
Analysis and countermeasure of abnormalities
SMGB0082 rev.1 - 07/2015
155
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 (air
heat-exchanger side)
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 over
-
current
protection
control (for
fan)
Activation
of over
-
current
protection
control for
compres
-
sor
Activation
of com
-
pressor
internal
thermo
Faulty fan motor bearing
It becomes locked
Replace fan motor
Single phase operation
Check electromagnetic switch
Replace electromagnetic switch
Decreased insulation of
motor
Measure insulation resistance
Replace fan motor
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
Faulty fan module
Inspection of Fan Module
Replace fan module
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 overcur
-
rent 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.
Air mixture
Try to open ventilator valve
Ventilator
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 exces
-
sively 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
Air mixture
Try to open ventilator valve.
Ventilator
Hot water temp too high
Check thermistor activation
Replace Thermistor
Refrigerant overcharge
Measure cycle temperature
Charge correct volume
