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Check method & Handling
(Without using MELANS)
(1) Outdoor unit address is set to “00”
(2) Erroneous address.
1
Address setting of indoor unit to be coupled with remote controller incorrect.
(Indoor unit = remote controller – 100.)
2
Address setting of remote controller incorrect.
(Remote controller = indoor unit + 100.)
(3) Faulty wiring of transmission terminal block TB5 of indoor unit in the same
group with remote controller.
(4) Centralized control SW2-1 of outdoor unit is turned ON.
(5) Disconnection or faulty wiring of indoor unit transmission line.
(6) Disconnection between indoor unit M-NET transmission line terminal block
(TB5) and connector CN2M.
(7) More than 2 sets of power supply connector (CN40) are inserted into
centralized control transmission line of outdoor unit.
(8) M-NET remote controller is connected to the terminal block of MA remote
controller.
(9) Faulty outdoor unit control circuit board.
(10) Faulty indoor controller board.
(11) Faulty remote controller.
(Interlocking control with MELANS)
(12) No grouping registration from MELANS (Neglecting to set the relation
between indoor unit and network remote controller).
(13) Disconnection of centralized control transmission line (TB7) at outdoor unit.
(14) Power supply connectors (CN40) of Multiple outdoor units are inserted into
transmission lines.
Or in the system to which power supply unit for transmission line, power
supply of the outdoor unit (CN40) is inserted into transmission line.
Factors
Phenomena
3
“HO” display on remote
controller does not disappear
and ON/OFF switch is
ineffective.
NO
NO
NO
YES
YES
YES
NO
YES
YES
YES
NO
NO
NO
YES
Same symptom for all
units in a single
refrigerant system?
Check outdoor unit
address
51 ~ 100?
Check centralized
control switch SW2-1 at
outdoor unit
ON?
Faulty outdoor unit
control circuit board
Confirm address of remote
controller with “HO” displayed
Indoor unit + 100?
Check address of
coupling indoor unit
Remote controller
-100?
Check voltage of indoor unit M-NET
transmission terminal block
17 ~ 30V?
Disconnection
Faulty indoor controller board
or remote controller
Address setting
miss of remote
controller
Indoor address
setting miss
Transmission line
wiring miss of
indoor unit M-NET
Disconnection
of CN2M
connector
Outdoor unit
address setting
miss
Switch setting
miss
Change from
ON to OFF
In case with MELANS used
When MELANS is used, “HO” display on the remote controller will disappear at the group registration of the indoor unit and local remote controller.
If “HO” does not disappear after the registration, check the items (11) ~ (13) in the Factors column.
Repair spot
in trouble
In case MELANS is not used
Check connection between indoor
unit M-NET transmission terminal
block (TB5) and connector CN2M