3“HO” display on re-
mote controller does
not disappear and
switch is ineffective.
Symptom Cause
(Without using MELANS)
1) Outdoor unit address is set to “00.”
2) Erroneous address
1Address setting miss of indoor unit to be coupled with remote controller
(Remote controller is not set to - 100.)
2Address setting miss of remote controller
(Indoor unit is not set to + 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) Faulty outdoor unit control circuit board
9) Faulty indoor controller board
10) Faulty remote controller
(Interlocking control with MELANS)
11) No grouping registration from MELANS (Neglecting to set the relation between indoor unit and net-
work remote controller)
12) Slipping off of centralized control transmission line (TB7) at outdoor unit
13) At system connected with MELANS, power supply connector (CN40) is inserted to centralized con-
trol transmission line of outdoor unit
In case no MELANS used
Same symptom for all
units in a single refriger-
ant system?
Check outdoor
unit address
51 ~ 100?
Check centralized control
switch SW2-1 at outdoor unit
ON?
Faulty outdoor unit
control circuit board
Outdoor unit
address set-
ting miss
Switch setting
miss
Make it ON
→OFF
Slipping off of
CN2M
connector
Repair spot
in trouble
Setting miss
of Fresh
Master SW3-1
Indoor unit + 100?
Check address of
coupling indoor unit
17 ~ 30V?
Slipping off?
Check Fresh Master SW3-1
ON?
Faulty indoor controller board
or remote controller
Check voltage of indoor unit M-
NET transmission terminal block
Address setting
miss of remote
controller
Indoor address
setting miss
Transmission line
wiring miss of in-
door unit M-NET
Check connection between indoor unit M-NET trans-
mission terminal block (TB5) and connector CN2M
YES
YES
NO
YES
NO
NO
YES
YES
YES
NO
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 12) ~ 14) in the Cause column.
Checking method & countermeasure
Remote controller
–100?
NO
NO
NO
YES
NO
Confirm address of remote
controller with "HO" displayed
YES
-
51
-