Table of Contents
SiUS341802E
Troubleshooting
Service Diagnosis
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
Check for details of error in
monitor mode.
U4-01
YES
Has the
indoor or
outdoor unit PCB
been replaced, or has
the indoor-outdoor or
outdoor-outdoor
transmission
wiring been
modified?
NO
Do all
indoor unit
remote controllers in
the same refrigerant
system display
U4?
YES
Reset the power supply once.
Does the
microcomputer
normal monitor
indication lamp (HAP)
on the outdoor
unit PCB
YES
Does the
seven-segment
display show (1) or (2)?
(∗1)
YES
The
lamp does not turn
OFF for a period of 12
minutes or more.
NO
Are the
indoor-outdoor
and outdoor-outdoor
transmission wirings
normal?
YES
Disconnect
the outdoor-outdoor
transmission wiring.
Does the system normally
operate with a single
transmission
line?
YES
NO
YES
Are the
indoor-outdoor and
NO
outdoor-outdoor
transmission wirings
normal?
NO
Is
voltage
between L1 and N
NO
terminals of the outdoor unit
PCB within ±10% of the
voltage range?
YES
Fuse on
NO
the outdoor unit PCB
has blown out.
NO
YES
NO
NO
Troubleshooting by Error Code
Refer to troubleshooting
U4-03
(Indoor unit system
transmission error)
Press and hold BS3 on the
master outdoor unit main
PCB for a period of 5
seconds or more. (The
system will not operate for a
period of 12 minutes at
maximum.)
YES
Replace the indoor unit PCB.
Modify the transmission
wirings.
Correct the voltage.
∗1. :OFF
:ON
:BLINK
(1)
SEG1 SEG2 SEG3
NO
(2)
YES
Replace the fuse.
Replace the outdoor unit
PCB.
Press and hold BS3 on the
outdoor unit main PCB for a
period of 5 seconds or more.
Modify the transmission
wirings.
Replace the outdoor unit main
PCB (A1P).
Mount the DIII-NET extension
adaptor.
260
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- Outdoor Unit
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Table of Contents
Troubleshooting
