Troubleshooting for MSP Duct Type Indoor Unit
SiSG121917E
135
Part 6 Service Diagnosis
6.8 Signal Transmission Error (Between Indoor Unit and
Remote Controller)
Error Code
U5
Method of Error
Detection
In case of controlling with 2 remote controllers, check the system using microcomputer if signal
transmission between indoor unit and remote controller (main and sub) is normal.
Error Decision
Conditions
Normal transmission does not continue for specified period.
Supposed
Causes
Connection of 2 main remote controllers (when using 2 remote controllers)
Defective indoor unit PCB
Defective remote controller
Transmission error caused by noise
Troubleshooting
Caution
Be s
u
re to t
u
rn off the po
w
er s
w
itch
b
efore connecting or disconnecting
connectors, or parts may
b
e damaged.
Is SS1 of
b
oth
remote controllers set to
MAI
N
?
N
O
N
O
YES
YES
N
O
Replace the indoor
u
nit
PCB (control PCB).
Set one remote controller to
SUB; t
u
rn the po
w
er s
u
pply
off once and then
b
ack on.
There is possi
b
ility of
malf
u
nction ca
u
sed
b
y noise.
Check the s
u
rro
u
nding area
and t
u
rn on again.
There is possi
b
ility of
malf
u
nction ca
u
sed
b
y noise.
Check the s
u
rro
u
nding area
and t
u
rn on again.
N
ormal
N
ormal
N
O
N
O
Using
2 remote controllers?
YES
YES
YES
Replace the remote controller.
Ret
u
rn to normal?
Ret
u
rn to normal?
N
O
Replace the indoor
u
nit PCB.
YES
Do the
ser
v
ice monitors of all
the indoor
u
nits
b
link?
Does
operation ret
u
rn
to normal
w
hen the
po
w
er is t
u
rned off
momentarily?
(R22251)