
10 Troubleshooting
Initial troubleshooting
SMGB0091 rev.2 - 11/2015
192
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Insufficient cooling process
Excessively
high discharge
pressure
Insufficient
air flow to the
RASC unit heat
exchanger
Clogging of the RASC unit
heat exchanger?
Remove the clogging
Obstacles at the inlet or the
outlet of the RASC unit heat
exchanger
Remove the obstacles
Is the service area for the
RASC unit sufficient?
Secure the service area
Correct fan speed?
Replace the fan motor
Excessively high
air temperature
to the RASC unit
heat exchanger
Short-circuited air to the
RASC unit?
Remove the cause of the
short-circuited air
Any other heat load near the
RASC unit?
Remove the heat source
Excessively
charged
refrigerant
Expansion valve opening
Correctly charge the refrigerant
Non-condensate
gas in cycle
Check each temperature and
each pressure
Charge the refrigerant after the
vacuum pumping
Clogging of the
discharge piping Check for clogging
Remove the clogging
Failure or
malfunction of
the expansion
valve
Check for clogging
Remove the clogging
Check the connection cord
and the connector
Replace the connector
Is there an operation sound
from the coil?
Replace the coil
Is the thermistor on the
compressor normal?
Replace the thermistor
Is the thermistor installed
correctly on the compressor? Correctly install the thermistor
Malfunction or internal leakage of
the 4-way valve
Check the temperature
difference at the inlet and the
outlet of the 4-way valve
Replace the 4-way valve
Excessively low
suction pressure
Malfunction or
internal leakage
of the 4-way
valve
Check the temperature
difference between the inlet
and the outlet of 4-way valve
Replace the 4-way valve
Failure of
solenoid valve
for bypass
Check refrigerant leakage of
solenoid valve
Replace solenoid valve
Discharge temperature of the indoor
unit is unstable
Check the expansion valve
of the indoor unit in the same
system
Replace the failed expansion
valve of the indoor unit