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The serial signal is not output
from outdoor unit to indoor unit.
• Miscabling of inter-unit cables
• Defective serial sending circuit
on outdoor P.C. board
• Defective serial receiving circuit
on outdoor P.C. board
• Compressor case thermo
operation
BUS communication circuit error
* BUS communication was
interrupted over the specified
time.
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.
Error in other cycles
• Indoor heat exchanger temp
(TC) does not vary after start of
cooling/ heating operation.
Coming-off, disconnection or
short of indoor temp sensor (TA)
Coming-off, disconnection or
short of indoor temp sensor (TC)
Coming-off, disconnection or
short of indoor temp sensor
(TCJ)
Error in indoor fan system
Revolutions frequency error of fan
Error in indoor unit or other
positions
1. EEPROM access error
Outside error input
Detected by input voltage level
from outside devices
Outside interlock input
Detected by input voltage level
from outside devices
Table 10-2-2
Operation of diagnostic function
Judgement and action
Block
Check
Symptom
Unit
Condition
code status
Operation
continues.
Operation
continues
(According
to remote
control of
indoor
unit)
Operation
continues.
Operation
continues.
Operation
continues.
Operation
continues.
Operation
continues.
All stop
Operation
continues.
Operation
continues.
All stop
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
Displayed when
error is detected
1. Outdoor unit does not completely
operate.
• Inter-unit cable check, correction of
miscabling
• Outdoor P.C. board check, P.C. board
cables 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
1. Communication line check, miscabling
check
Power supply check for central control
(Central control remote control, etc.)
and indoor unit
2. Communication check (XY terminal)
3. Indoor P.C. board check
4. Central control check
(Communication P.C. board)
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).
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).
1. Check indoor temp sensor (TA).
2. Check indoor P.C. board
(Main P.C. board).
1. Check indoor temp sensor (TC).
2. Check indoor P.C. board
(Main P.C. board).
1. Check indoor temp sensor (TCJ).
2. Check indoor P.C. board (Main P.C.
board).
1. Check indoor fan motor connector
circuit (CN210).
2. Check indoor fan.
3. Check indoor P.C. board
(Main P.C. board).
1. Check indoor P.C. board
(EEPROM and peripheral circuits)
(Main P.C. board).
1. Check outside devices.
2. Check indoor P.C. board
(Main P.C. board).
[MODE]
[TIMER] lamp
5Hz flash
[MODE] lamp
5Hz flash
[MODE] lamp
5Hz flash
*
*: No display in the setting at shipment