Malfunction Of Transmission Between Indoor And Outdoor Unit (U4 Or Uf) - Daikin FCQ35B7V1 Service Manual

Error Codes: System Malfunctions

Malfunction of Transmission between Indoor and Outdoor Unit (U4 or UF)

3.2
1
Error code
Error generation
Causes
3 3
Troubleshooting 1
4
5
Caution
3–46
U4 UF
or
The error is generated when the microprocessor detects that the transmission between the indoor and
the outdoor unit is not normal over a certain amount of time.
The possible causes are:
Wiring indoor-outdoor transmission wire is incorrect
Malfunctioning indoor unit PCB
Malfunctioning outdoor unit PCB
Outside cause (noise...).
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.
Is HAP flashing?
YES
Check of
indoor unit
microcomputer
normal
HAP
Is HAP flashing?
Check of
YES
indoor unit
transmission
malfunction
HBP
To outdoor unit
(next page)
Be sure to turn off power switch before connect or disconnect connector, or parts damage may be
occurred.
NO (ON or OFF)
Turn the power supply off
once and then back on.
Is H1P flashing?
YES
NO
Is H2P on?
NO (OFF)
Does
outdoor unit
NO
microcomputer
normal H1P
flash?
YES
Is
indoor-outdoor
YES
transmission wire
connected
correctly?
ESIE05-04
NO
Failure of indoor unit PCB or
malfunction of power supply
system.
Resets normally.
Could be outside cause (noise...).
YES
Failure of indoor unit PCB.
NO
Wire correctly.
Part 3 – Troubleshooting