SiUS281117
Symptom-based Troubleshooting
96
Service Diagnosis
1. Symptom-based Troubleshooting
Symptom
Supposed Cause
Countermeasure
1
The system does not start operation at all.
Blowout of fuse(s)
Turn OFF the power supply and
then replace the fuse(s).
Cutout of breaker(s)
• If the knob of any breaker is in
its OFF position, turn ON the
power supply.
• If the knob of any circuit
breaker is in its tripped position,
do not turn ON the power
supply.
2
The system starts operation but makes an
immediate stop.
Blocked air inlet or outlet of indoor
or outdoor unit
Remove obstacle(s).
Clogged air filter(s)
Clean the air filter(s).
3
The system does not cool or heat air well.
Blocked air inlet or outlet of indoor
or outdoor unit
Remove obstacle(s).
Clogged air filter(s)
Clean the air filter(s).
Enclosed outdoor unit(s)
Remove the enclosure.
Improper set temperature
Set the temperature to a proper
degree.
Airflow rate set to "LOW"
Set it to a proper airflow rate.
Improper direction of air diffusion
Set it to a proper direction.
Open window(s) or door(s)
Shut it tightly.
[In cooling] Direct sunlight received
Hang curtains or shades on
windows.
[In cooling] Too many persons staying in a
room
The model must be selected to
match the air conditioning load.
[In cooling] Too many heat sources (e.g. OA
equipment) located in a room
4
The system does
not operate.
The system stops and
immediately restarts operation.
If the OPERATION lamp on the
remote controller turns ON, the
system will be normal. These
symptoms indicate that the
system is controlled so as not to
put unreasonable loads on the
system.
Normal operation. The system will
automatically start operation after
a lapse of 5 minutes.
Pressing the TEMP ADJUST
button immediately resets the
system.
The remote controller displays
"UNDER CENTRALIZED
CONTROL", which blinks for a
period of several seconds
when the OPERATION button
is depressed.
The system is controlled with
centralized controller. Blinking
display indicates that the system
cannot be operated using the
remote controller.
Operate the system using the
COOL/HEAT centralized remote
controller.
The system stops immediately
after turning ON the power
supply.
The system is in preparation
mode of micro-computer
operation.
Wait for a period of approximately
1 minute.
5
The system
makes
intermittent
stops.
The remote controller displays
error codes "
U4
" and "
U5
", and
the system stops but restarts
after a lapse of several
minutes.
The system stops due to an
interruption in communication
between units caused by
electrical noises coming from
equipment other than air
conditioners.
Remove causes of electrical
noises.
If these causes are removed, the
system will automatically restart
operation.
ON
OFF
Knob
Tripped
Circuit breaker
