LG FM15AH UL3, Svc Manual

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Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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Part 3 Control logic
2.1 Frequency control
Frequency that corresponds to each rooms capacity will be determined according to the difference in the temperature of
each room and the temperature set by the remote controller.
There are various factors determining the frequency.
1. Indoor unit capacity value.
2. Temperature compensation factor
3. Initial frequency setting
2.2 Primary step setting
: Capacity steps of compressor are decided by
∑
Qj (Summation of capacity code), TA0(Outdoor temp.), TAI(Indoor
temp.), DTAI (Step Compensation of temperature difference Indoor Temp. and Setting Temp.
Comp Step = (Step base+Long piping compensation) x
∆
Step TAO x
∆
Step TAI x
∆
Step DTAI
✽
Target frequency step (Step base) exceeds maximum step, the Step base value follows the maximum step value.
✽
The compressor get the minimum step in case Step base value is lower than the minimum step of operating
capacity.
2. Step(frequency) control
System
ON/Setting
Indoor
data
Outdoor
data
Calculation of
set frequency
Start
system
Continues
check
To & fro
feedback
Indoor temperature
Indoor capacity
Indoor On/OFF
Selected fan speed
Outdoor
Temperature
Basic formula of
calculation
Compressor setting
Stop
system
System
error
Step base Standard frequency step by
∑
Qj (Summation of capacity code)
Long piping Comp. Step compensation by setting long piping
∆
Step TAO step compensation by TAO (Outdoor temp.)
∆
Step TAI step compensation by TAI (Indoor temp.)
∆
Step DTAI Step Compensation of temperature difference Indoor Temp. and Setting Temp.