Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook page 88

Symptom
3 "HO" display on re- (Without using MELANS)
mote controller does 1) Heat source unit address is set to "000."
not disappear and 2) Erroneous address.
switch is ineffective.
3) Faulty wiring of transmission terminal block TB5 of indoor unit in the same group with remote
4) Centralized control SW2-1 of heat source unit is turned ON.
5) Setting to interlocking system from indoor unit (Switch 3-1 = OFF), while Fresh Master is intended to
6) Disconnection or faulty wiring of indoor unit transmission line.
7) Disconnection between indoor unit M-NET transmission line terminal block (TB5) and connector
8) More than 2 sets of power supply connector (CN40) are inserted into centralized control transmis-
9) Faulty heat source 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
13)Slipping off of centralized control transmission line (TB7) at heat source unit.
14)At system connected with MELANS, power supply connector (CN40) is inserted to centralized
Checking method & countermeasure
In case no MELANS used
Same symptom for all
units in a single refriger-
ant system?
YES
Check heat source
unit address
51 ~ 100?
YES
Check centralized
control switch SW2-1 at
heat source unit
ON?
NO
Faulty heat source unit
control circuit board
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.
1 Address setting miss of indoor unit to be coupled with remote controller.
(Indoor unit = remote controller - 100.)
2 Address setting miss of remote controller.
(Remote controller = indoor unit + 100.)
controller.
use by remote controller operation (indoor unit attribute).
CN2M.
sion line of heat source unit.
network remote controller).
control transmission line of heat source unit.
NO
Heat source
NO
unit address
setting miss
Switch setting
YES
miss
Make it ON
→ OFF
Repair spot
in trouble
Cause
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
Slipping off of
YES
CN2M
connector
NO
Setting miss of
Fresh Master
SW3-1
–85–
Confirm address of remote
controller with "HO" displayed
Indoor unit + 100?
Check address of
coupling indoor unit
Remote controller
-100?
YES
Check voltage of indoor unit M-
NET transmission terminal block
17 ~ 30V?
YES
Slipping off?
NO
Check Fresh Master SW3-1
ON?
YES
Faulty indoor controller board
or remote controller