Daikin FCQ50B7V1 - Malfunction of Transmission between Indoor and Outdoor Unit (U4 or UF)

Error Codes: System Malfunctions ESIE05-04
3–46 Part 3 – Troubleshooting
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3.2 Malfunction of Transmission between Indoor and Outdoor Unit (
U4
or
UF
)
Error code U4 or UF
Error generation 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.
Causes The possible causes are:
Q Wiring indoor-outdoor transmission wire is incorrect
Q Malfunctioning indoor unit PCB
Q Malfunctioning outdoor unit PCB
Q Outside cause (noise...).
Troubleshooting 1 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.
Caution Be sure to turn off power switch before connect or disconnect connector, or parts damage may be
occurred.
Turnthepowersupplyoff
onceandthenbackon.
Checkof
indoorunit
microcomputer
normal
HAP
Checkof
indoorunit
transmission
malfunction
HBP
FailureofindoorunitPCBor
malfunctionofpowersupply
system.
Resetsnormally.
Couldbeoutsidecause(noise...).
FailureofindoorunitPCB.
Wirecorrectly.
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO(OFF)
NO(ONorOFF)
Tooutdoorunit
(nextpage)
IsHAPflashing?
IsHAPflashing?
Is
indoor-outdoor
transmissionwire
connected
correctly?
Does
outdoorunit
microcomputer
normalH1P
flash?
IsH2Pon?
IsH1Pflashing?