40
Installation and Maintenance
Service Manual
NO.
Malfunction
Name
Display Method of Indoor Unit
Display Method of Outdoor
Unit
A/C status
Possible Causes
Dual-8
Code
Display
Indicator Display (during
blinking, ON 0.5s and OFF
0.5s)
Indicator has 3 kinds of
display status and during
blinking, ON 0.5s and OFF
0.5s
Operation
Indicator
Cool
Indicator
Heating
Indicator
Yellow
Indicator
Red
Indicator
Green
Indicator
11
Gathering
refrigerant
Fo
OFF 3S
and blink
1 times
OFF 3S OFF 1S
and blink and blink
1 times 17 times
When the outdoor unit receive
signal of Gathering refrigerant
,the system will be forced to
run under cooling mode for
gathering refrigerant
Nominal cooling mode
12
Indoor
ambient
temperature
sensor is
open/short
circuited
F1
OFF 3S
and blink
once
During cooling and drying
operation, indoor unit operates
while other loads will stop;
during heating operation,
the complete unit will stop
operation.
1. Loosening or bad contact of
indoor ambient temp. sensor and
mainboard terminal.
2. Components in mainboard fell
down leads short circuit.
3. Indoor ambient temp. sensor
damaged.(check with sensor
resistance value chart)
4. Mainboard damaged.
13
Indoor
evaporator
temperature
sensor is
open/short
circuited
F2
OFF 3S
and blink
twice
AC stops operation once
reaches the setting
temperature. Cooling, drying:
internal fan motor stops
operation while other loads
stop operation; heating: AC
stop operation
1. Loosening or bad contact of
Indoor
evaporator temp. sensor and
mainboard terminal.
2. Components on the mainboard
fall
down leads short circuit.
3. Indoor evaporator temp. sensor
damaged.(check temp. sensor
value
chart for testing)
4. Mainboard damaged.
14
Outdoor
ambient
temperature
sensor is
open/short
circuited
F3
OFF 3S
and blink
3 times
OFF 1S
and
blink
6 times
During cooling and drying
operating, compressor stops
while indoor fan operates;
During heating operation,
the complete unit will stop
operation
Outdoor temperature sensor
hasnt been connected well or
is damaged. Please check it by
referring to the resistance table for
temperature sensor)
15
Outdoor
condenser
temperature
sensor is
open/short
circuited
F4
OFF 3S
and blink
4 times
OFF 1S
and
blink
5 times
During cooling and drying
operation, compressor stops
while indoor fan will operate;
During heating operation,
the complete unit will stop
operation.
Outdoor temperature sensor
hasnt been connected well or
is damaged. Please check it by
referring to the resistance table for
temperature sensor)
16
Outdoor
discharge
temperature
sensor is
open/short
circuited
F5
OFF 3S
and blink
5 times
OFF 1S
and
blink
7 times
During cooling and drying
operation, compressor will sop
after operating for about 3
mins,
while indoor fan will operate;
During heating operation, the
complete unit will stop after
operating for about 3 mins.
1.Outdoor temperature sensor
hasnt been connected well or is
damaged. Please check it by
referring to the resistance table for
temperature sensor)
2.The head of temperature sensor
hasnt been inserted into the copper
tube
17
Limit/
decrease
frequency
due to
overload
F6
OFF 3S
and blink
for 6
times
OFF 1S
and
blink
3 times
All loads operate normally,
while
operation frequency for
compressor is decreased
Refer to the malfunction analysis
(overload, high temperature
resistant)
18
Decrease
frequency
due to
overcurrent
F8
OFF 3S
and blink
8 times
OFF 1S
and
blink
once
All loads operate normally,
while
operation frequency for
compressor is decreased
The input supply voltage is too low;
System pressure is too high and
overload
