41
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
44
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
45
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
46
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.
47
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.
48
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
49
50
Defrosting
oE
OFF 3S
and blink
once
(during
blinking,
ON 10s
and OFF
0.5s)
Not the error code. It’s the
status code for the operation.
Cool: compressor and outdoor
fan stops operation, while
indoor fan operates; Heat:
compressor, outdoor fan and
indoor fan stop operation.
1. Outdoor ambient temperature
exceeds the operation range of unit
(eg: less than-20oC or more than
60oC for cooling; more than 30oC
for heating);
2. Failure startup of compressor?
3. Are wires of compressor not
connected tightly?
4. Is compressor damaged?
5. Is main board damaged?
Its the normal state
Undefined
outdoor unit
error
