U4" Malfunction Of Transmission (Between Indoor And Outdoor Unit) - Daikin SkyAir RZQ200 · 250C7Y1B Service Manual

SiBE26-701
4.38 "U4" Malfunction of Transmission (between Indoor and
Outdoor Unit)
U4
Remote
Controller
Display
Applicable RZQ
All models of indoor units
Models
Method of Microcomputer checks if transmission between indoor and outdoor units is normal.
Malfunction
Detection
Malfunction When transmission is not carried out normally for a certain amount of time
Decision
Conditions
Supposed
Causes
Troubleshooting Diagnosis of incorrect or broken/disconnected wiring
If the LEDs on the indoor unit PC board are off, it indicates that the transmission wiring between
indoor and outdoor units may be incorrect or broken/disconnected.
Troubleshooting
Wiring indoor-outdoor transmission wire is incorrect.
Outside cause (noise, etc.)
Failure of indoor unit PC board
Failure of outdoor unit PC board
Failure of outdoor unit fan
Power supply -open phase etc.
Be sure to turn off power switch before connect or disconnect connector,
Caution
or parts damage may be occurred.
Are the
connections of
wiring connecting indoor
and outdoor units
proper?
YES
Turn OFF the power
supply once and then
turn it ON again.
"U4" display recurs.
YES
Check HAP (microcomputer
normal monitor) on the
outdoor PC board.
A
NO
NO
Diagnosis by Remote Controller
Wire properly.
(Correct faulty wiring
and wrong wire type.)
The indoor PC board is
normal.
Check for external
factors (noise, etc.).
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