Daikin R42NUY2S - Page 396

Troubleshooting by Remote Controller Si20-701_B
389
Troubleshooting
YES
YES
NO
NO
YES
NO
NO
Has
the indoor
or outdoor unit
PCB been
replaced, or has the
indoor - outdoor or
outdoor - outdoor
unit transmission
wiring been
modified?
All
indoor unit
remote controllers
of the same refrigerant
system display
"U4".
Is
indoor -
outdoor and
outdoor - outdoor unit
transmission wiring
normal?
Press and hold
the RESET
button on the
master outdoor
unit PCB for 5
seconds.
∗ The unit will not
operate for up
to 12 minutes.
Supply
220~240V.
Reset the power supply.
YES
The
voltage
between
terminals L1 and N of
the outdoor unit PCB
is 220~240 V
±10%.
Replace the fuse.
Replace the
outdoor unit
PCB.
The
fuse on the
outdoor unit PCB is
burnt.
NO
YES
Outdoor unit
PCB micro-
computer monitor
(HAP) blinks.
Caution
Be sure to turn off the power switch before
connecting or disconnecting connectors, or parts
may be damaged.
A
YES
Replace the
indoor unit PCB
indicated by the
error code "
U4".
NO
Fix the
indoor/outdoor or
outdoor/outdoor
unit transmission
wiring.