Mitsubishi Electric PURY-P200 Service Handbook page 153

Phenomena
2 When turning on the remote
controller operation SW, a
temporary operation display is
indicated, and the display
lights out immediately, and the
unit stops.
Check method & Handling
Same symptom
for all units in a single
refrigerant system?
YES
Self-diagnosis LED
checks
7120 error display?
NO
Check for Item (1)
For the check method, follow
"Outdoor unit transmission power
source circuit failure judgment"
Factors
(1) The power for the M-NET
transmission line is not supplied
from the outdoor unit.
(2) Short circuit of the transmission line.
(3) Incorrect wiring of the M-NET
transmission line on the outdoor
unit side.
1 Disconnected wire for the MA
remote controller and
disconnected line to the terminal
block.
2 The indoor transmission line is
connected incorrectly to terminal
block (TB7) to the transmission
line for centralized control.
3 The power supply connectors
(CN40) for multiple outdoor units
are inserted.
Or the power supply connector
(CN40) for outdoor unit is inserted
in the system to which the power
supply unit for transmission line is
connected.
(4) Disconnected M-NET transmission
line on the indoor unit side.
(5) Disconnected wire between
terminal block (TB5) to the M-NET
transmission line of the indoor unit
and the indoor controller board
(CN2M) or disconnected connector.
NO
YES
Check for the Factor
(2) and (3)
9.[4].8.(2)
Handle the problems
- 150 -
Checke method & Handling
When the factor (2) and (3)
apply, self-diagnosis LED works
and the check code 7102 will be
displayed.
Check voltage of the terminal
block (TB5) to the transmission
line of the indoor unit
NO
Check for Item (5)
Check for Item (5)
YES
Handle the problems
Failure of the indoor unit
controller board or the MA
remote controller
17-30V?
YES
Problems?
NO