57
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
