Haier HBU-18CF03 - Page 72

Commercial Air Conditioner Model: HBU-18CF03
HDU-42CF03/H HPU-42HF03
72
Diagnose and troubleshooting:
1) Sensor failure
no
no
no
yes
yes
yes
yes
Replace PCB
Is DC voltage between
both ends of sensor
near 5V or 0V?
Replace sensor
Is sensor resistance
acceptable?
Replace sensor
Is sensor short-circuit
or open-circuit?
check if the wiring is
correct according to
wiring diagram
no
reconnect
Relocate
if sensor is fixed
well
2) Communication failure between operation panel and indoor unit
start
if the wired controller
and indoor PCB are
compatible
if terminals A,B,C,D on
wired controller are
corresponding with
terminals of indoor PCB
if terminals A,B,C,D of
wired controller are in
open circuit or
connected well
if terminals A,B(or
C,D)of wired controller
are short circuit
change wired
controller
wire correctly
wire correctly
wire correctly
yes
yes
yes
yes
no
no
no