Service Manual
42
Installation and Maintenance
No. Malfunction
Name
Display
Method of
Indoor Unit
A/C status
Possible Reasons
Dual-8
Code
Display
39
The four-way
valve is
abnormal
U7
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
4-way valve doesn’t change direction under
heating mode.
40
Outdoor unit
zero cross
error
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Outdoor unit sensing AC
power zero cross circuit is
ineffective.
41
Outdoor DC fan
motor malfunction
L3
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Outdoor fan error.
42
Selection port
electrical level
is abnormal.
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Model’s selection port
electrical level is abnormal.
43
PFC current
offset voltage
is wrong.
HC
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
PFC current offset voltage
is wrong.
44
Pipe covering
middle tube
temperature
sensor error
F4
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Pipe covering middle tube
temperature sensor error
45
Humidity
sensor error
L1
Air conditioner can work normally.
Humidity sensor error
46
Communication
error between
indoor unit and
check board
JF
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Communication error
between indoor unit and check board
47
Radio
frequency
module error
rF
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Radio frequency module error
48
Voltage is too
high
oE
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are
stopped.
DC voltage after power
rectification is too high.
49
Outdoor fan
phase loss
Cooling: Compressor stops and indoor fan
operates. Heating: All the loads
are stopped.
Outdoor fan power phase
loss.
50
Outdoor fan
nonsynchronism
Cooling: Compressor stops and indoor fan
operates. Heating: All the loads are stopped.
Outdoor fan non-synchronism
51
Phase current
protection frequency
limit/ frequency
decrease
Loads are running normally.
Compressor operating frequency is decreased.
Compressor phase current
is too large.
52
Outdoor ambient
temperature is
abnormal.
Cooling: Compressor stops and indoor fan
operates. Heating: All the loads are stopped.
Outdoor ambient
temperature is too high or
too low.
53
Fan current
sensing circuit
error
Cooling: Compressor stops and
indoor fan operates. Heating: All the loads are
stopped.
Fan current sensing circuit
is abnormal.
54
Peak current
frequency limit
or decrease
Loads are running normally.
Compressor operating frequency is decreased.
PFC peak current is too large.
55
Fluorine shortage
protection,
refrigerant
circulation cut-off
protection.
F0
Cooling: Compressor stops
and indoor fan operates.
Heating: All the loads are stopped.
Air conditioner is short of
fluorine. Valve doesn’t
open. System is blocked.