10 Troubleshooting
Troubleshooting procedure
SMGB0091 rev.2 - 11/2015
204
Phenomenon
Cause
Check item
Action
(Turn OFF the main switch)
Activation of the
high-pressure
switch due to the
excessively high
discharge pressure
(PSH)
Excessively high temperature air to
the indoor unit during heating mode
Calculate the heat load
Reduce the heat load or use a
bigger unit if possible
Check for hot air near the
ceiling (heating)
Provide good circulation
Check for short-circuited air
(heating)
Remove the short-circuited air
Check if there is any heat
source near the unit
Remove the heat source
Faulty high-
pressure switch
Faulty pressure
switch
Measure the discharge
pressure. Check the continuity
after the decrease of the
pressure
Replace the pressure switch
if faulty
Insufficient
contacting
Measure the resistance using
the tester
Fix the looseness.
Replace the connector
Incorrect
connection
Check the connections
Repair the connections
Faulty or malfunction of the
expansion valve
Check for clogging
Remove the clogging
Check the connect wiring and
the connectors
Replace the connector
Check the operation sound
from the coil
Replace the coil
Check the discharge gas
thermistor
Replace the thermistor
Check the attaching state of
the discharge gas thermistor
Reattach the thermistor
Disconnected of the connector
or coil not well assembled
Fix the looseness or reconnect
the connector
Fully closed and locked
Replace the expansion valve
Faulty gas bypass solenoid valve
Check for clogging
Replace the gas bypass
solenoid valve
Overcharged refrigerant
Check the cycle operation
temperature
Charge the refrigerant correctly
Mixture of the non-condensate gas in
the refrigerant cycle
Check the air temperature and
the pressure
Recharge the refrigerant after
the vacuum pumping
Clogging of the discharge piping
Check for clogging
Remove the clogging
Liquid or gas line stop valve does not
operate correctly
Check the stop valves
Fully open the stop valves
Clogging of the check valve
Check for clogging
Replace the check valve
Faulty magnetic
contactor switch
No power is supplied to the coil
Check connections
Set the connections properly.
No power at the magnetic contactor
Measure the resistance using
a tester
Replace the magnetic switch if
it is broken
Variable frequency
driver failure
(VFD)
(LED ALM on VFD:
ON (*) )
Over temperature of the VFD device
Check the temperature in the
installation area
Ensure that the installation
area has a proper ventilation
so that ambient temperature
around the unit does never
exceed 46ºC
Faulty variable frequency driver
-
Replace the variable frequency
driver
?
N O T E
(*): Once the VFD contactor is open, the LED ALM on VFD is turned OFF after few seconds. Therefore, pay attention when revising the
VFD, since the LED ALM may be OFF even though the alarm 02 has been caused due to VFD failure.