–83–
4 “HO” indication on
the remote controller
is not lit, and the
ON/OFF switch does
not work.
1) The M-NET transmission power supply from the
outdoor unit is not supplied.
1 The original power supply of Indoor Unit is not
turned on.
2 The connector on the controller board in Indoor
Unit is removed.
Main board ----CNS1, CNVCC3
INV board----CNAC2, CNVCC1, CNL2
3
D
efects in the power supply circuit of the
outdoor unit
(For detail, refer to Pages 127)
●
INV board defects
●
Diode stack defects
●
Prevention resistance of rush current (R1)
damage.
2) Short circuit of the M-NET transmission line.
3) Erroneous wiring of the M-NET transmission line on
the outdoor unit side.
1 Broken transmission line or terminal block
removal
2 Indoor Unit transmission line is wired to the
transmission line terminal block (TB7) for the
central control by mistake.
4) M-NET transmission line break on the Indoor Unit
(Short/ Open) side.
5) Loose or disconnection of wiring between the
M-NET transmission terminal block (TB 5) of Indoor
Unit and Indoor Unit controller board CN2M and
disconnection of connectors.
6) Erroneous wiring of the MA remote control.
1 Short circuit of the MA remote wiring
2 Broken MA remote control line (No.2) and
disconnection
of the terminal block connection
3
Reversed wiring, cross-over in the group control
4 Mis-wiring of MA remote control to the terminal
block (TB5) for the transmission line
5 Mis-wiring of M-NET transmission line to the
MA remote control terminal block (TB13)
7) The unit address is not “00” as it should be with
automatic address setting.
8) The address of
Indoor Unit
exceeds 50.
9) The master and slave setting of the MA remote
control becomes the slave setting.
10)Use of M-NET (vs. MA) remote controller when
using automatic address setting.
11)Defective room controller board (MA remote
communication circuits).
12)Defective remote controller.
Check method and Remedy
Symptom Cause
In the case of 2), 3) and 7)
factors, indicate 7102 errors
by the self-diagnosis LED of
the outdoor unit.
NO
NO
YES
YES
NO
YES
YES
Check 2) and 3) in the
“cause” column.
Correct the problem.
Is error code 7120 displayed?
Check item 11).
Check item 4).
19 ~ 12V?
Check items 5), 6), 8),
9), and 10).
Defective indoor unit
controller board or
MA remote control
Was the problem found?
Correct the problem.
Check the voltage at
the terminal block
(TB15) for the transmission
line of the indoor unit.
NO
The same symptoms
appear in all units in the same
refrigerant system.
Self-diagnosis LED
checks
YES
NO
Was the problem
found?
Check item 1).
Change the M-NET
remote control to the
MA remote control.
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