Hitachi SAMURAI Series Service Manual page 131

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