Hisense KFR-72LW Maintenance Manual page 34

Fault self-test code 5
Communication
failure
Are all the lead wires
connected between indoor no
and outdoor unit?
yes
Power indicator(LED) of
outdoor control board(PCB) yes
light up?
no
Is the 3.15A fuse of
yes
outdoor PCB blown?
no
Is the20A fuse of
yes
outdoor PCB blown?
no
Reactor, filter board is
yes
open-circuit?
no
Silicon bridge rectifier has
yes
AC Input?
no
The startup resistor input
yes
voltage is normal?
no
The filter is open-circuit? yes
no
Is the 20A fuse blown? yes
no
Is there power input
between 1 and 2 on terminal yes
block of outdoor unit?
no
Is there power output
between 1 and 2 on terminal yes
block of indoor unit?
no
Indoor Main
Relay(RY01) has yes
output?
no
Indoor control board
fault and replace it
Connect the indoor and
outdoor unit again
according to the wiring
diagram
Open air-conditioners
after replacing the
outdoor control board
Outdoor control board is
no
breakdown or short-circuit？
yes
Outdoor control board
fault and replace it
Connection wire
trouble and check
Replace the
trouble unit
Silicon bridge
rectifier trouble
and replace it
Startup resistor is
no
heating?
yes
Startup resistor
isshort-circuit.
Filter Substrate Failure
and replace it
Connection wire
trouble and check
Connection wire
trouble and check
Connection wire
trouble and check
Connection wire
trouble and check
Page 33 of 37
Indoor control board
fault and replace it
no
Air-conditioner is Outdoor control board
yes
normal?
The IPM board is
breakdown or short-
no
circuit？
yes
Replace the IPM
board and the fuse.
Outdoor short-circuit fault. The
cable, control board, IPM,
electrolytic capacitors and other cells
are short-circuit or breakdown?
Startup resistor
fault
IPM, control board,
filter substrate is short-
circuit or breakdown
The control system of outdoor
unit has short circuit trouble,
check the connection
wire,outdoor control
board,Silicon Bridge, IPM,
rectifier and electrolyse
capacitor
Display board fault
and replace it
no
Air-conditioner is Indoor control board
yes
normal? fault and replace it
fault and replace it
Normal protection
and replace fuse
Replace the
trouble unit
Replace the
trouble unit
Replace the
trouble unit