31
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
19
Decrease
frequency 
due to
high air
discharge
F9
OFF 3S
and 
blink
twice
All loads operate normally, 
while
operation frequency for
compressor is decreased
Overload or temperature is too 
high; 
Refrigerant is insufcient;
Malfunction of electric expansion 
valve (EKV)
20
Limit/
decrease
frequency 
due to
antifreezing
FH
OFF 3S
and 
blink
4 times
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
OFF 3S
and 
blink
13 times
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 its normal, theres malfunction 
for the circuit, please replace the 
control panel (AP1)
22
Voltage of 
DC bus-bar 
is too low 
PL
OFF 3S
and 
blink
12 times
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 its normal, theres malfunction 
for the circuit, please replace the 
control panel (AP1)
23
Compressor 
Min 
frequence in 
test state
P0
Showing during min. cooling or 
min. heating test
24
Compressor 
rated 
frequence  in 
test state
P1
Showing during nominal cooling or 
nominal heating test
25
Compressor 
maximum 
frequence in 
test state
P2
Showing during max. cooling or 
max. heating test