Troubleshooting
Service Manual
170
Initial troubleshooting
SMGB0066 rev.0 - 12/2009
Abnormal operation of the devices (Cont.)
observed failure
Cause
Check item
Action
(Turn off the main
switch)
Unit stopped in heating
operation
High cut caused by
Pd (high pressure)
surpassing
Insufficient water flow
Check the water
temperature difference
between inlet and outlet
Increase the water flow
Too much refrigerant
Check clogging of
discharge side pipe
Remove the clogging
Clogging of the expansion
valve
Check clogging of
discharge side pipe
Remove the clogging
Clogging strainer (not
water)
Check the temperature
difference before/after
strainer
Replace or cleaning
strainer
Clogging of the 4-way
valve
Check the clogging
Remove the clogging or
replace the 4-way valve
Water scale attaching
inside the water side heat
exchanger
Check the water side
exchanger
Chemical cleaning
Excessively high water
outlet temperature
Check water temperature
Check the installation
Excessively high
discharge gas
temperature (too much
super-heat)
Malfunction of the 4-way
valve and also internal
leakage
Check gas leakage or
shortage of refrigerant
Replace the 4-way valve
Malfunction of check
valve
Replace check valve
Clogging of the expansion
valve
Remove the clogging
Clogging of the refrigerant
side strainer
Replace or clean the
strainer
Failure discharge gas
temperature thermistor
Measure the resistance of
thermistor
Replace the thermistor
Failure liquid bypass
solenoid valve
Check solenoid valve
Replace the solenoid
valve
Clogging of the solenoid
liquid solenoid bypass
capilary
Clogging of capilary
Replace capilary
Over current compressor
Excesive current
consumption
Voltage supply too high/
low
Check the limits in
"working range".
(I-III phase)
Check the interface
impedance or power
supply
Measure each interface
voltage & contact the
electrical coMPany
Excessively high pressure
in the high pressure
sensor
Check the cause
Single or double phase
operation (only 3 phase
model)
Check the main fuse
Replace the fuse
Check the loose of the
screw power supply
terminal
Tighten the screw
Check contact point or
magnetic contact for
compressor
Replace magnetic contact