Protection Control; Discharge Temperature Control - LG universal system air conditioner Service Manual

Outdoor Units

3. Protection control

3.1 Discharge Temperature control

3.1.1 Discharge pipe control for Inverter compressor
1) There can be two situations
(a) Sensor is failed (error code for sensor failure will be generated)
(b) Abnormal high temperature discharge temperature (error code for high discharge will be generated)
Both cases unit will stop.
2) Compressor working
(a) If discharge pipe temperature £º T1 No limitation on compressor frequency
(b) T2 ≤ discharge pipe temperature £º T off (Hysteresis control) Compressor frequency down by 5Hz and
expansion valve up by 10 pulse in every 1 min.
(c) Discharge pipe temperature ≥ Toff Compressor will be off
Toff(105)°C
T2(95)°C
T1(90)°C
COMP
Set
Hz
Expansion
Set
valve
146 Universal System Air Conditioner
D-Pipe temp
5 Hz
Set
Down
10
Set
Pulse Up
5 Hz
OFF
Down
10
Stop control
Pulse Up
Set