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Symptoms
< Diagnostic Method and Remedy >
Causes
Diagnostic Method and Remedy
1
2
There is no
response when
pressing Power ON
on the remote
controller
(Power-on indicator
on the remote
controller is off)
1) No power is supplied to the indoor unit by the transformer
1
Main switch of the indoor unit is off
2
Connectors (CND, CNT, CN3T) on the indoor controller board
are unplugged
3
Fuses on the indoor controller board are blown out
4
Transformer on the indoor unit is not working, Torn wires
2) MA remote controller line is wired incorrectly
1
MA remote controller line is torn or disconnected from terminal
board
2
Short-circuited MA controller line
3
MA remote controller line is wired incorrectly
4
MA remote controller line is connected to TB5
5
MA remote controller line is accidentally connected to AC 200V
power-source line terminal
6
MA remote controller line is accidentally connected to M-NET
Transmission line terminal in the indoor unit
3) More than the permissible number of remote controllers (2) are
connected to the unit
4) The length or diameter of MA remote controller does not meet the
specifications
5) Remote Display Output line on the indoor unit is short-circuited or
the relays are connected with wrong polarities
6) Faulty indoor controller board
7) Problems with MA remote controller
a) Check MA remote controller terminal
voltage (between A and B)
a. Voltage between DC9-12
→
Problem with remote controller
b. No voltage
• Check items 1 and 3 on the left
→
Correct the problem if found.
• If neither 1 nor 3 applies
→
Go to b)
b) Disconnect the remote controller line
from TB13 on the indoor unit, and
check the voltage between A and B.
a. Voltage between DC 9-12
→
Check items 2) and 4) on the
left. Correct the problem if found.
b. No voltage
• Check 1) on the left again.
→
Correct the problem if found.
• If no problem is found with item
1), check Remote Display Line
(i.e. polarity of the relay)
• If still no problem is found,
replace the indoor controller
board.
Display on the LED
remains for a few
seconds then
disappears when
turning on power
with the remote
controller
1) M-NET Transmission is powered by the outdoor unit
1
Main switch on the outdoor unit is OFF.
2
Connectors on the main board of the outdoor unit are unplugged
Main controller board ·············· CNS1, CNVCC3
Inverter board ························· CNDC2, CNVCC2, CNL2
Gate-amp terminal board ········ CNDC1
3
Faulty outdoor power supply circuit
• Blown fuse on G/A board (F01)
• Damaged diode stack
• Faulty Inverter board
• Surge breaker resistance (R1) loss
2) Shorted transmission line
3) Faulty wiring of M-NET transmission line on the outdoor unit
1
Torn transmission line, disconnected line from terminal
2
Indoor transmission line accidentally connected to TB7
4) Torn M-NET line on the indoor unit
5) Disconnected lines or unplugged connectors between M-NET
transmission terminal (TB5) and Indoor controller board CN2M
If one of the items 1)-5) on the
left is the cause, LED5 (M-NET
Transmission voltage indicator)
on the indoor controller board
will be off.
When 2) or 3) is the cause, error
message 7102 will be displayed
on the self-diagnosis LED on
the outdoor unit.
YES
NO
YES
NO
YES
YES
NO
NO
Self-Diagnoses LED Check
Check the voltage of trans-
mission terminal board TB15
Faulty MA remote
controller or indoor
controller board
Check items
2) and 3)
Check item 4)
9~12V?
Check item 5)
Fix any problems
found
Fix any problems
found
Check item 1)
Are all units in the
refrigerant circuit experiencing
the same problem?
Is Error Code 7102 displayed?
Was the
problem solved?
[4] Troubleshooting using information on problems with Remote Control, Input from
External Source
(1) MA Remote Control
