---- When outdoor fan speed is lower than 
300RPM or higher than 2400RPM for 60 second, 
the whole unit stops and LED displays failure. 
7.3.4 Inverter module Protection. 
----Inverter module protection itself has a 
protection function against current, voltage and 
temperature. If these protections happened, the 
corresponding code will display on indoor unit 
LED and A/C will stop. The unit will recover 3min 
delay after the protection disappeared.  
7.3.5 Low voltage protection 
VOLT_RST1_ADD
VOLTAGE
No limit
VOLT_LTM1_ADD
VOLT_RST2_ADD
VOLT_LTM2_ADD
VOLT_LTM_FREQ1_ADD
VOLT_LTM_FREQ2_ADD
 
Note: if the low voltage protection occurs and not 
resumes within 3min, it will keep the protection 
always after restart the machine.  
7.3.6 Compressor current limit protection 
If the compressor current exceeds the current 
limit value for 10 seconds, the compressor 
frequency will be limited as below table. 
Cooling mode: 
Decrease the frequency to 
COOL_F4 and run at COOL_F4 
for 3 minutes. 
 
After that, the frequency will be 
adjusted according to the capacity 
demand and rise to the upper 
level every 3 minutes 
(When the frequency>COOL_F4 
via capacity demand). 
If the current frequency is lower than COOL_F4, the frequency will 
not be limited. 
After 10s of the compressor start, if the current>ICOOL, the AC will 
display the failure for 30 seconds and stop. The AC will restart 3 
minutes later. 
Heating mode: 
Decrease the frequency to 
HEAT_F4 and run at HEAT_F4 for 
3 minutes. 
 
After that, the frequency will be 
adjusted according to the capacity 
demand and rise to the upper 
level every 3 minutes 
(When the frequency>Heat_F4 via 
capacity demand). 
If the current frequency is lower than HEAT_F4, the frequency will 
not be limited. 
After 10s of the compressor start, if the current>IHEAT, the AC will 
display the failure for 30 seconds and stop. The AC will restart 3 
minutes later. 
7.3.7 Indoor / outdoor units communication 
protection 
If the indoor units cannot receive the feedback 
signal from the outdoor units for 2 minutes, the 
AC will stop and display the failure. 
7.3.8 High condenser coil temp. protection. 
When T3>65℃ for 3 seconds, the compressor 
will stop while the indoor fan and outdoor fan will 
continue.  
When T3<52℃, the protection will release and 
the compressor will restart after 3 minutes. 
7.3.9 Outdoor unit anti-freezing protection 
When T2B<0℃ for 250 seconds, the indoor unit 
capacity demand will be zero and resume to 
normal when T2B>10℃. 
7.3.10 Oil return 
Running rules: