LG ARNU Series, Service Manual

Page: 92 / 226

92 Outdoor Unit
1.1 Normal operation
Note: Heating operation is not functional at an outdoor air temperature of 27°C or more
1.2 Compressor control
Fuzzy control : Maintain evaporating temperature(Te) to be constant on cooling mode and condensing tem-
perature(Tc) on heating mode by Fuzzy control to ensure the stable system performance.
(Tc:47 ~51°C, Te:2 ~ 5°C)
(1) Cooling mode
Te can be set by initial dip switch setting. (Normal mode, capacity up mode, and energy save mode)
(2) Heating mode
Tc can be set by initial dip switch setting. (Normal mode, capacity up mode, and energy save mode)
1.3 Main LEV control
Main LEV operates with fuzzy control rules to keep the degree of super Heat(Superheat) (about 3°C)at the
evaporator outlet stable during heating mode
The degree of Superheat = Tsuction - Tevaporation
Tsuction : temperature at suction pipe sensor(°C)
Tevaporation : evaporation temperature equivalent to low pressure(°C)
1.4 Fan control
The fan motors of the main unit are operated by the inverter drive with fuzzy control rules.
1. Basic control
Compressor
Fan
Main LEV
4 way valve
Subcooling
LEV
Fuzzy control
Fuzzy control
Full open
Off
Fuzzy control
Fuzzy control
Fuzzy control
Fuzzy control
On
min.
Cooling operation Heating operation Actuator
stop
stop
After 15min,
min. pulse
After 15min, Off
After 15min,
min. pulse
Stop state
Function