LG Universal System Air Conditioner Service Manual page 137

3.3 Inverter Protection control(2)
3.3.1 Function
: Power module failure protection by checking the temperature of heat sink.
There is a temperature sensor for checking the heat sink temperature.
3.3.2 Heat sink sensor failure error
Short Check : if temperature ≥130°C
Open Check : if temperature < - 30°C
System will go in self diagnosis (error 65) is displayed and product stops.
3.3.3 Heat sink temperature control
a) Heat sink temperature < T2
b) T2 ≤ heat sink temperature < Toff : Compressor frequency down by 5 Hz
c) Heat sink temperature ≥ Toff
System will stop if this situation occurs 5 times in 1 hour and error code will be generated also self diagnosis will
start.
If high temperature situation occurs 5 times in 1 hr system counts 1 error and after that 4 times if this situation
occurs system stops and give error code.
If the temperature reached Toff condition system will count 5 times after that and system will stop with error
code.
Toff=85°C
T2=75°C
T1=70°C
COMP
Hz
: No limitation on compressor frequency
: Compressor will be off.
Heat Sink temp
Set
5 Hz
frequency
Down
Set
5 Hz
frequency
Down
Outdoor Units
Set
OFF
frequency
Service Manual 137