Toshiba MMY-MUP0961HT6P-UL Service Manual page 139

7-5-4. Connected Indoor/Outdoor Unit Quantity Check
(In checking the number of connected outdoor units and connected indoor units after address setup, a
lower number of connected units is displayed (There are outdoor/ indoor units that do not operate in a test
operation))
Status
Miswiring of communication lines between outdoor units
The number of
or an unconnected wire ( Fig. 4). (Address setup
connected outdoor
operation finished without recognizing a miswired
units is few.
follower unit.)
Miswiring of communication lines between indoor units
The number of
or an unconnected wire ( Fig. 5). (Address setup
connected indoor
operation finished without recognizing a miswired indoor
units is few.
unit.)
The indoor remote controller is not connected with wire.
Miswiring of the indoor remote controller
The number of
indoor units
connected to a
Indoor remote controller communication circuit trouble
group is few in
If 220 V is incorrectly applied to the remote controller
groupoperation
terminal, the remote controller communication circuit
from an indoor
fails.
remote controller.
Cause
- 139 -
Counter measures
After improvement of wiring, set up the addresses again
and check the number of connected outdoor units.
After modification of wiring, set up the addresses again and
check the number of connected indoor units.
Using the main indoor remote controller connected to a group,
start a test operation, specify the unit that is not operating (the
unit not connected to the group), and then check the wiring.
Using the main indoor remote controller connected to a group,
start a test operation and then specify the unit that is not
operating (the unit not connected to the group). Remove the
quick connect terminal connected to remote controller
terminals A/B, and check the voltage. If voltage is not applied
(normally 15 to18 V), replace the PC board.