Malfunction Of Transmission Between Indoor Units - Panasonic Urban Multi MX1R Series Service Manual

PACD011001C2
3.28

Malfunction of Transmission Between Indoor Units

U4 U4 U4 U4
Remote Controller
Display
„ Indoor to outdoor,outdoor to outdoor crossover wiring, disconnection or short circuit
Supposed Causes
„ Outdoor unit power supply is OFF
„ System address doesn't match
„ Defect of indoor unit PC board
„ Defect of outdoor unit PC board
Troubleshooting
Troubleshooting Urban Multi "MX1R, ME1R Series" Using R-407C
Be sure to turn off power switch before connect or disconnect connector,
Caution
or parts damage may be occurred.
Has
the indoor or
outdoor unit PC
board been replaced,
or has the indoor - outdoor or
outdoor - outdoor unit
transmission wiring
been modified?
NO
All
indoor unit
remote controllers of the same
refrigerant system
display "U4."
YES
Reset the power supply.
Outdoor unit PC
board microcomputer monitor
(HAP) blinks.
YES
Operation
ready lamp (H2P) is
blinking.
YES
Wait to lamp goes off.
Is
indoor - outdoor and
NO
outdoor - outdoor unit
transmission wiring
normal?
YES
YES
Is indoor
- outdoor and outdoor -
NO
outdoor unit transmission
wiring normal?
NO
The voltage
between terminals R
NO
and S of the outdoor unit PC
board is 220~240 V
(60Hz) or 220 V
(50 Hz).
YES
The fuse on
the outdoor unit's PC board
is burnt.
NO
The secondary
voltage of the transformer is
about 30 V.
YES
NO
Troubleshooting
Push and hold the RESET button
on the outdoor unit PC Board for
5 seconds.
∗ The unit will not operate for
up to 12 minutes.
YES
Replace the indoor unit PC Board.
Fix the indoor/outdoor unit
transmission wiring.
NO
Supply 220~240 V.
YES
Replace the fuse.
NO
Replace the transformer.
Replace outdoor unit PC board.
Fix the indoor/outdoor unit
transmission wiring.
Replace the outdoor unit PC
Board.
(VF054)
371