51
Installation and Maintenance
Service Manual
NO.
Malfunction
Name
Display Method of Indoor Unit
A/C status
Possible Causes
Dual-8
Code
Display
Indicator Display (during
blinking, ON 0.5s and OFF
0.5s)
Operation
Indicator
Cool
Indicator
Heating
Indicator
42
Malfunction of
phase current
detection
circuit for
compressor
U1
During cooling and drying
operation, compressor will stop
while indoor fan will operate;
During heating operation, the
complete unit will stop
Replace outdoor control panel AP1
43
Malfunction of
voltage
dropping for
DC bus-bar
U3
During cooling and drying
operation, compressor will stop
while indoor fan will operate;
During heating operation, the
complete unit will stop
Supply voltage is unstable
44
Malfunction
of complete
units current
detection
U5
During cooling and drying
operation, the compressor will
stop while indoor fan will
operate;
During heating operating,
the complete unit will stop
operation.
Theres circuit malfunction on
outdoor units control panel AP1,
please replace the outdoor units
control panel AP1.
45
The four-way
valve is
abnormal
U7
If this malfunction occurs
during
heating operation, the complete
unit will stop operation.
1.Supply voltage is lower than
AC175V;
2.Wiring terminal 4V is loosened or
broken;
3.4V is damaged, please replace
4V.
46
Zero-
crossing
malfunction of
outdoor unit
U9
During cooling operation,
compressor will stop while
indoor fan will operate; during
heating,the complete unit will
stop operation.
Replace outdoor control panel AP1
47
48
49
Defrosting
Malfunction
of zero-cross
detection
circuit
Malfunction
of detecting
plate(WIFI )
U8
JF
OFF 3S
and blink
once
(during
blinking,
ON 10s
and OFF
0.5s)
Defrosting will occur in
heating
mode. Compressor will
operate
while indoor fan will stop
The complete unit stops
Loads operate normally,
while the unit can’t be
normally controlled by APP.
1. Main board of indoor unit is
damaged;
2. Detection board is damaged;
3. The connection between
indoor unit and detection board
is not good;
operation.
Its the normal state
1.Power supply is abnormal;
2.Detection circuit of indoor
control mainboard is abnormal.
