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8.3 Main Protection 
8.3.1 Three minutes delay at restart for 
compressor 
Less than 1 minute delay for the 1
st
 time 
stand-up and 3 minutes delay for others. 
8.3.2 Temperature protection of compressor 
top 
The unit will stop working when the compressor 
top temp. protector cut off, and will restart after 
the compressor top temp. protector restart. 
8.3.3 Temperature protection of compressor 
discharge 
Compressor discharge temp. T5>115℃(239°F) 
for 5s, compressor stops. 
8.3.4 Fan speed is out of control 
When Indoor fan speed keeps too low 
(300RPM) for certain time, the unit will stop and 
the LED will display the failure 
8.3.5 Inverter module protection 
The Inverter module has a protection function 
about current, voltage and temperature. If these 
protections happen, the corresponding code 
will display on indoor unit and the unit will stop 
working. 
8.3.6 Indoor fan delayed open function 
When the unit starts up, the louver will be active 
immediately and the indoor fan will open 10s 
later. 
If the unit runs in heating mode, the indoor fan 
will be also controlled by anti-cold wind 
function. 
8.3.7 Compressor preheating functions 
Preheating permitting condition: 
When T4(outdoor ambient temperature)<
3°C(37.4°F), the preheating function will be 
activated. 
8.3.8 Sensor protection at open circuit and 
breaking disconnection. 
When there’s only one temperature sensor in 
malfunction , the air conditioner will keep 
working but show the error code, in case of any 
emergency use. 
When there’s more than one temperature 
sensor in malfunction, the air conditioner will 
stop working 
8.3.9 Zero crossing detection error 
protection 
If AC detects time interval is not correct, the unit 
will stop and the LED will display the failure. 
8.3.10 Refrigerant leakage detection 
This function is only active in cooling mode. It 
can better prevent the compressor being 
damaged by refrigerant leakage or compressor 
overload. 
Open condition: 
When compressor is active, the value of the 
Coil temperature of evaporator T2 has no 
change or very little change.