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
11 Gathering
refrigerant
Fo
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
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
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
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
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
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
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
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
