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8-4-4. Check Code Table
Error mode detected by indoor unit (1)
*
: No display in the setting at shipment
Operation of diagnostic function
Block
display
Check
code A
Check
code B
Cause of operation
Status of air
conditioner
Condition
Judgment and measures
The serial signal is not output
from outdoor unit to indoor
unit.
• Miswiring of inter-unit wires
• Defective serial sending
circuit on outdoor P.C.
board
• Defective serial receiving
circuit on outdoor P.C.
board
• Compressor case thermo
operation
Operation
continues
Displayed when
error is detected
1. Outdoor unit does not completely
operate.
• Inter-unit wire check, correction
of miswiring
• Outdoor P.C. board check, P.C.
board wires check
• Compressor case thermo check
2. In normal operation
When outdoor sending serial LED
(Green) flashes, the receiving serial
LED (Orange) also flashes. : Indoor
P.C. board (Main P.C. board) check
When the receiving serial LED
(Orange) does not flash: Outdoor
P.C. board check
BUS communication circuit
error
* BUS communication was
interrupted over the
specified time.
Operation
continues
(According to
remote
controller of
indoor unit)
Displayed when
error is detected
1. Communication line check,
miswiring check
Power supply check for central
controller (Central control remote
controller, etc.) and indoor unit
2. Communication check (XY
terminal)
3. Indoor P.C. board check
4. Central controller check
(Communication P.C. board)
[MODE]
[TIMER] lamp
5Hz flash
Network address miss-setting
• Addresses of central
controllers (Central control
remote controller, etc.) are
duplicated.
Operation
continues
Displayed when
error is detected
1. Check central control system
network address setting. (SW02)
2. Indoor P.C. board check
3. Central controller check
(Communication P.C. board)
Error in 4-way valve system
• Indoor heat exchanger
temperature rise after start
of cooling operation.
• Indoor heat exchanger
temperature fall after start
of heating operation.
Operation
continues
Displayed when
error is detected
1. Check 4-way valve.
2. Check 2-way valve and non-return
valve.
3. Check indoor heat exchanger
sensor (TC).
4. Check indoor P.C. board
(Main P.C. board).
*
Error in other cycles
• Indoor heat exchanger
temp (TC) does not vary
after start of cooling/heating
operation.
Operation
continues
Displayed when
error is detected
1. Compressor case thermo operation
2. Coming-off of detection part of
indoor heat exchanger sensor
3. Check indoor heat exchanger
sensor (TC).
4. Check indoor P.C. board
(Main P.C. board).
Coming-off, disconnection or
short of indoor temp sensor
(TA)
Operation
continues
Displayed when
error is detected
1. Check indoor temp sensor (TA).
2. Check indoor P.C. board
(Main P.C. board).
Coming-off, disconnection or
short of indoor temp sensor
(TC)
Operation
continues
Displayed when
error is detected
1. Check indoor temp sensor (TC).
2. Check indoor P.C. board
(Main P.C. board).
[MODE] lamp
5Hz flash
Coming-off, disconnection or
short of indoor temp sensor
(TCJ)
Operation
continues
Displayed when
error is detected
1. Check indoor temp sensor (TCJ).
2. Check indoor P.C. board
(Main P.C. board).