14
Installation and Maintenance
Service Manual
No. Malfunction Name
Display Method
of Indoor Unit
A/C status
Possible Causes
Dual-8 Code
Display
12
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.
13
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 hasn't been
connected well or is damaged. Please
check it by referring to the resistance table
for temperature sensor)
14
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 hasn't 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 hasn't been
connected well or is damaged. Please
check it by referring to the resistance table
for temperature sensor)
2.The head of temperature sensor hasn't
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
R e fe r to th e ma l fu n cti o n a n a l ysi s
(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
19
Decrease frequency
due to high air
discharge
F9
All loads operate normally, while operation
frequency for compressor is decreased
Overload or temperature is too high;
Refrigerant is insufficient;
Malfunction of electric expansion valve
(EKV)
20
Limit/decrease
frequency due to
antifreezing
FH
All loads operate normally, while operation
frequency for compressor is decreased
Poor air-return in indoor unit or fan speed
is too low
21 Voltage for DC bus-
bar is too high
PH
During cooling and drying operation,
compressor will stop while indoor fan will
operate;
During heating operation, the complete
unit will stop operation.
1. Measure the voltage of position L and
N on wiring board (XT), if the voltage is
higher than 265VAC, turn on the unit after
the supply voltage is increased to the
normal range.
2.If the AC input is normal, measure the
voltage of electrolytic capacitor C on
control panel (AP1), if it's normal, There's
malfunction for the circuit, please replace
the control panel (AP1)
22 Voltage of DC bus-
bar is too low
PL
During cooling and drying operation,
compressor will stop while indoor fan will
operate;
During heating operation, the complete
unit will stop
1. Measure the voltage of position L and
N on wiring board (XT), if the voltage is
higher than 150VAC, turn on the unit after
the supply voltage is increased to the
normal range.
2.If the AC input is normal, measure the
voltage of electrolytic capacitor C on
control panel (AP1), if it's normal, There's
malfunction for the circuit, please replace
the control panel (AP1)
9. Maintenance
