Symptom-Based Troubleshooting - Daikin FCQ18PVJU Service Manual

Symptom-based Troubleshooting

1. Symptom-based Troubleshooting
Symptom
1 The system does not start operation at all.
2 The system starts operation but makes an
immediate stop.
3 The system does not cool or heat air well.
4 The system does The system stops and
not operate. immediately restarts operation.
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 stops immediately
after turning ON the power
supply.
5 The system The remote controller displays
makes malfunction codes "U4" and
intermittent "U5", and the system stops but
stops. restarts after a lapse of several
minutes.
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Supposed Cause
Blowout of fuse(s)
Cutout of breaker(s)
Power failure
Blocked air inlet or outlet of indoor
or outdoor unit
Clogged air filter(s)
Blocked air inlet or outlet of indoor
or outdoor unit
Clogged air filter(s)
Enclosed outdoor unit(s)
Improper set temperature
Airflow rate set to "LOW"
Improper direction of air diffusion Set it to a proper direction.
Open window(s) or door(s)
[In cooling] Direct sunlight received
[In cooling] Too many persons staying in a
room
[In cooling] Too many heat sources (e.g. OA
equipment) located in a room
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.
The system is controlled with
centralized controller. Blinking
display indicates that the system
cannot be operated using the
remote controller.
The system is in preparation
mode of micro computer
operation.
The system stops due to an
interruption in communication
between units caused by
electrical noises coming from
equipment other than air
conditioners.
SiUS28-902_a
Countermeasure
Turn Off the power supply and
then replace the fuse(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.
ON
Knob
Tripped
OFF
Circuit breaker
After the power failure is reset,
restart the system.
Remove obstacle(s).
Clean the air filter(s).
Remove obstacle(s).
Clean the air filter(s).
Remove the enclosure.
Set the temperature to a proper
degree.
Set it to a proper airflow rate.
Shut it tightly.
Hang curtains or shades on
windows.
Normal operation. The system will
automatically start operation after
a lapse of five minutes.
Operate the system using the
COOL/HEAT centralized remote
controller.
Wait for a period of approximately
one minute.
Remove causes of electrical
noises.
If these causes are removed, the
system will automatically restart
operation.
Troubleshooting