Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook

Page: 143 / 204

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Symptom Cause
3 (Without using MELANS)
1) Outdoor unit address is set to “000.”
2) Erroneous address.
1
Address setting miss of indoor unit to be coupled with remote controller.
(Indoor unit address = Remote controller address – 100.)
2
Address setting miss of remote controller.
(Remote controller address = Indoor unit a 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) Setting to interlocking system from indoor unit (Switch 3-1 = OFF), while Fresh Master is intended to
use by remote controller operation (indoor unit attribute).
6) Disconnection or faulty wiring of indoor unit transmission line.
7) Disconnection between indoor unit M-NET transmission line terminal block (TB5) and connector CN2M.
8) More than 2 sets of power supply connector (CN40) are inserted into centralized control transmission
line of outdoor unit.
9) Faulty outdoor unit control circuit board.
10) Faulty indoor controller board.
11) Faulty remote controller.
12) The transmission booster is defective or the power supply has been cut-off.
(Interlocking control with MELANS)
13) No grouping registration from MELANS (Neglecting to set the relation between indoor unit and
network remote controller).
14) Slipping off of centralized control transmission line (TB7) at outdoor unit.
15) At system connected with MELANS, power supply connector (CN40) is inserted to centralized control
transmission line of outdoor unit.
16) The transmission booster is defective or the power supply has been cut-off.
“HO” display on re-
mote controller does
not disappear and
switch is ineffective.
Checking method & countermeasure
Check outdoor unit
address
Same symptom for all
units in a single refriger-
ant system?
In case no MELANS used
51 ~ 100?
Check centralized control
switch SW2-1 at outdoor unit
ON?
Faulty outdoor unit
control circuit board
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
Outdoor unit
address
setting miss
Switch setting
miss
Make it ON
→
OFF
Repair spot
in trouble
Address setting
miss of remote
controller
Indoor
address
setting miss
Transmission
line wiring miss
of indoor unit
M-NET
Slipping off
of CN2M
connector
Setting miss of
Fresh Master
SW3-1
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 ~ 30 V?
Check connection between indoor unit M-NET trans-
mission terminal block (TB5) and connector CN2M
Slipping off?
Check Fresh Master SW3-1
ON?
Faulty indoor controller
board or remote controller
---------------------------------------------------------------------------------------------------------------------
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.
YES
YES
NO
YES