Service Manual

8. Troubleshooting
190
SMGB0079 rev.0 - 01/2013
Phenomenon Cause Check item
Action
(Turn OFF the main switch)
Insufcient heating
process
Indoor heat load is greater than the heating ca-
pacity
Calculate the heat load
Replace the unit with a bigger
unit
Excessively low suction
pressure
Gas leakage or insuf-
cient refrigerant charge
Measure superheat
Correctly charge the refrigerant
after the gas leakage check and
repairing
Excessively small di-
ameter or long piping
Measure the eld supplied
piping
Use the specied pipes
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 com-
pressor normal?
Replace the thermistor
Is the thermistor installed cor-
rectly on compressor?
Correctly install the thermistor
Clogging of I.U./O.U.
strainer
Check the temp. difference
between the inlet and the outlet
of strainer
Replace the strainer for the out-
door unit or the indoor unit
Clogging of suction
piping
Check the temp. difference of
each part
Remove the clogging
Insufcient air ow
through the outdoor
unit heat exchanger
Is the outdoor unit heat ex-
changer clogged?
Remove the clogging
Are there any obstacles at the
inlet or the outlet of outdoor
unit?
Remove the obstacles
Is the service area for the out-
door unit sufcient?
Secure a sufcient service area
Check the speed of the outdoor
unit fan
Replace the fan motor
Excessively low air
temp. through the
outdoor unit heat ex-
changer
Check for any short-circuited
air to the outdoor unit
Remove the cause of the short-
circuited air
Defrosting is insuf-
ciently completed
Check the thermistor for the
defrost operation
Replace the thermistor for the
defrost operation
Excessively high dis-
charge pressure
Insufcient air ow to
the indoor unit heat
exchanger
Check the lter for a clogging Remove the clogging
Check for any obstacles at the
inlet or the outlet of the indoor
unit
Remove the obstacles
Check the indoor fan speed Replace the fan motor
Excessively high air
temp. to the indoor unit
heat exchanger
Check whether or not the short-
circuited air exists
Remove the cause of the short-
circuited air
Excessively charged
refrigerant
Check the refrigerant quantity
*4)
Correctly charge the refrigerant
Non-condensate gas in
ref. cycle
Check the refrigerant quantity
*4)
Recharge the refrigerant after
the vacuum pumping
Clogging of the dis-
charge pr. piping
Check for clogging Remove the clogging
Malfunction or internal leakage of the 4-way valve
Check the temp. difference at
the inlet and the outlet of the
4-way valve
Replace the 4-way valve
Malfunction of the check valve of the outdoor unit
Check the temp. difference at
the inlet and the outlet of the
check valve
Replace the check valve
Excessively high suction
pressure
Malfunction or internal
leakage of 4-way valve
Check the temp. difference at
the inlet and the outlet of the
4-way valve
Replace the 4-way valve
Discharge temp. 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