DAIKIN INVERTER AC ERROR CODES
DAIKIN INVERTER
AC
ERROR CODES
Indoor Unit
FTXS30LVJU
FTXS36LVJU
Outdoor Unit
RKS30LVJU
RKS36LVJU
U0
Refrigerant Shortage
Refrigerant shortage detection I:
Refrigerant shortage is detected by checking the input current value and the
compressor running frequency. If the refrigerant is short, the input current is lower than the
normal value.
Refrigerant shortage detection II:
Refrigerant shortage is detected by checking the discharge pipe temperature and
the opening of the electronic expansion valve. If the refrigerant is short, the discharge pipe
temperature tends to rise.
Refrigerant shortage detection III:
Refrigerant shortage is detected by checking the difference between suction and
discharge
temperature.
Supposed Causes
Disconnection of the discharge pipe thermostat,
indoor or outdoor heat exchanger thermostat, room or outdoor temperature
thermistor
Closed stop valve
Refrigerant shortage (refrigerant
leakage)
Poor compression performance of
compressor
Defective electronic expansion valve.
U2
Low-voltage Detection or Over-voltage Detection
Indoor Unit
The zero-cross detection of the power supply is evaluated by the indoor unit
PCB.
Outdoor Unit
Low-voltage detection:
An abnormal voltage drop is detected by the DC voltage detection circuit.
Over-voltage detection:
An abnormal voltage rise is detected by the over-voltage detection circuit.
Supposed Causes
Supply voltage is not as specified.
Defective DC voltage detection circuit
Defective over-voltage detection circuit
Defective PAM control part
Disconnection of compressor harness
Noise
Momentary fall of voltage
Momentary power failure
Defective indoor unit PCB
U4
Signal Transmission Error (between Indoor Unit and Outdoor Unit)
The data received from the outdoor unit in
indoor unit-outdoor unit signal transmission is checked whether it is normal.
The data sent from the outdoor unit cannot be
received normally, or the content of the data is abnormal.
Supposed Causes
Wiring error
Breaking of the connection wires between the indoor and outdoor units (wire No.
3)
Defective outdoor unit PCB
Defective indoor unit PCB
Disturbed power supply waveform.
U7
Signal Transmission
Error on Outdoor Unit PCB
Communication error between microcomputer
mounted on the main microcomputer and PM1.
The abnormality is determined when the
data sent from the PM1 can not be received for 9
seconds.
The error counter is reset when the data
from the PM1 can be successfully received.
Supposed Causes
Defective outdoor unit PCB.
UA
Unspecified Voltage
The supply power is detected for its
requirements (different from pair type and multi type) by the
indoor / outdoor transmission signal.
The pair type and multi type are interconnected.
Supposed Causes
Wrong models interconnected
Wrong wiring of connecting wires
Wrong indoor unit PCB or outdoor unit
PCB mounted
Defective indoor unit PCB
Defective outdoor unit PCB
E1
Outdoor Unit PCB Abnormality
The
system checks if the microprocessor is working in order.
The system checks if the zero-cross
signal comes in properly.
The microprocessor program runs out of
control.
The zero-cross signal is not detected.
Supposed Causes
Defective outdoor unit PCB
Broken harness between PCBs
Noise
Momentary fall of voltage
Momentary power failure, etc.
E5
OL Activation
A compressor overload is detected through
compressor OL.
If the error repeats, the system is shut
down.
Reset condition: Continuous run for
about 60 minutes without any other error
* The
operating temperature condition is not specified.
Supposed Causes
Defective discharge pipe thermistor
Defective electronic expansion valve or
coil
Defective FourWay valve or coil
Defective outdoor unit PCB
Refrigerant shortage
Water mixed in refrigerant
Defective stop valve.
E6
Compressor Lock
A compressor lock is detected by checking the
compressor running condition through the position detection circuit.
09/12 class
Operation stops due to over current.
If the error repeats, the system is shut
down.
Reset condition: Continuous run for
about 11 minutes without any other error
15/18/24/30/36 class
A compressor lock is detected by the
current waveform generated when applying high frequency voltage to the motor.
If the error repeats, the system is shut
down
Reset condition: Continuous run for
about 5 minutes without any other error.
Supposed Causes
Compressor locked
Compressor harness disconnected
E7
DC Fan Lock
An error
is determined with the high-voltage fan motor rotation speed detected by the
Hall IC.
The fan does not start in 15 ~ 30
seconds (depending on the model) even when the fan motor is running.
If the error repeats, the system is shut
down.
Reset condition: Continuous run for
about 11 minutes (09/12 class) or 5 minutes (15/18/24/30/ 36 class) without any
other error.
Supposed Causes
Foreign matter stuck in the fan
Defective fan motor
Defective outdoor unit PCB
E8
Input Over current Detection
An input overcurrent is detected by checking the
input current value with the compressor running.
The current exceeds about 9.25 ~ 20 A
for 2.5 seconds with the compressor running.
(The upper limit of the current decreases when the outdoor temperature exceeds
a certain
level.)
Supposed Causes
Outdoor temperature is out of operation
range.
Defective compressor
Defective power module
Defective outdoor unit PCB
Short circuit
EA
FourWay Valve Abnormality
The room temperature thermistor and the indoor
heat exchanger thermistor are checked if they
function within their normal ranges in each operation mode.
A following condition continues over 1 ~ 10 minutes after operating for 5 ~ 10
minutes.
Cooling / Dry
(room thermistor temp. – indoor heat exchanger temp.) < –5°C (–9°F)
Heating
(indoor heat exchanger temp. – room thermistor temp.) < –5°C (–9°F)
If the error repeats, the system is shut
down.
Reset
condition: Continuous run for about 60 minutes without any other error.
Supposed Causes
Disconnection of fourway valve coil
Defective fourway valve, coil, or
harness
Defective outdoor unit PCB
Defective thermistor
Refrigerant shortage
Water mixed in refrigerant
Defective stop valve
F3
Discharge Pipe Temperature Control
An error is determined with the temperature
detected by the discharge pipe thermistor.
Supposed Causes
Defective discharge pipe thermistor
(Defective outdoor heat exchanger thermistor or outdoor temperature thermistor)
Defective electronic expansion valve or
coil
Refrigerant shortage
Defective fourway valve
Water mixed in refrigerant
Defective stop valve
Defective outdoor unit PCB
F6
High Pressure Control in Cooling
High-pressure control (operation halt, frequency
drop, etc.) is activated in cooling operation if the
temperature sensed by the outdoor heat exchanger thermistor exceeds the limit.
Supposed Causes
The installation space is not large
enough.
Dirty outdoor heat exchanger
Defective outdoor fan motor
Defective stop valve
Defective electronic expansion valve or
coil
Defective outdoor heat exchanger
thermistor
Defective outdoor unit PCB
H0
Compressor System Sensor Abnormality
The
system checks the DC current before the compressor starts.
The DC current before compressor
start-up is out of the range 0.5 ~ 4.5 V (sensor output
converted to voltage value)
The DC
voltage before compressor start-up is below 50 V.
Supposed Causes
Broken or disconnected harness
Defective outdoor unit PCB
H0
The
system checks the supply voltage and the DC voltage before the compressor
starts.
The system checks the compressor current
right after the compressor starts.
The supply voltage and the DC voltage is
obviously low or high.
The compressor current does not run when
the compressor starts.
Supposed Causes
Disconnection of reactor
Disconnection of compressor harness
Defective outdoor unit PCB
Defective compressor
H6
Position Sensor Abnormality
A compressor start-up failure is detected by
checking the compressor running condition through the position detection circuit.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 11 minutes (09/12 class) or 5 minutes
(15/18/24/30/ 36 class) without any other error
Supposed Causes
Disconnection of the compressor relay
cable
Defective compressor
Defective outdoor unit PCB
Start-up failure caused by the closed
stop valve
Input voltage is outside the specified
range.
H8
DC Voltage / Current Sensor
Abnormality
DC voltage or DC current sensor abnormality is
identified based on the compressor running
frequency and the input current.
If the error repeats, the system is shut
down.
Reset
condition: Continuous run for about 60 minutes without any other error
Supposed Causes
Defective outdoor unit PCB
H8
CT or Related Abnormality
A CT or related error is detected by checking the
compressor running frequency and CT-detected input current.
Supposed Causes
Defective power module
Broken or disconnected wiring
Defective reactor
Defective outdoor unit PCB
H9,J3,J6,P4
Thermistor or Related Abnormality
(Outdoor Unit)
This fault is identified based on the thermistor
input voltage to the microcomputer. A thermistor fault is identified based on
the temperature sensed by each thermistor.
Supposed Causes
Disconnection of the connector for the
thermistor
Defective thermistor corresponding to
the error code
Defective heat exchanger thermistor in
the case of J3 error (outdoor heat exchanger thermistor in cooling operation,
or indoor heat exchanger thermistor in heating operation)
Defective outdoor unit PCB
L3
Electrical Box Temperature Rise
An electrical box temperature rise is detected
by checking the radiation fin thermistor with the compressor off.
Supposed Causes
Defective outdoor fan motor
Short circuit
Defective radiation fin thermistor
Disconnection of connector
Defective outdoor unit PCB
L4
Radiation Fin Temperature Rise
A radiation fin temperature rise is detected by
checking the radiation fin thermistor with the
compressor on.
Supposed Causes
Defective outdoor fan motor
Short circuit
Defective radiation fin thermistor
Disconnection of connector
Defective outdoor unit PCB
Silicon grease is not applied properly
on the radiation fin after replacing the outdoor unit PCB.
L5
Output Overcurrent Detection
An output overcurrent is detected by checking
the current that flows in the inverter DC section.
Supposed Causes
Poor installation condition
Closed stop valve
Defective power module
Wrong internal wiring
Abnormal power supply voltage
Defective outdoor unit PCB
Defective compressor
