LG LT-E1820CL Service Manual page 19

8. Defrost Control (18k, 24k)
• While in heating mode operation in order to protect the evaporator pipe of the outdoor unit from freezing, reversed to
cooling cycle to defrost the evaporator pipe of the outdoor unit.
• Defrost control is available 45 min. later since heating mode operation started, and it will not prolong over 10 min.
• Defrost control is carried out according to the following priority order while in heating mode operation.
1st priority : Defrost control is carried out according to the indoor pipe temp 60 min. later since heating mode opera-
tion started.
2nd priority : The temp differences between the indoor pipe temp and the intake air temp 25 min. later( T1) and 45
min. later ( T2) since heating mode operation started are measured, then defrost control is carried out
according to the dirrerence ( T= T1- T2)
3rd priority : Defrost control is carried out according to the temp difference (E=TE1-TE2) between the indoor pipe
temperatures of 25 min later(TE1) and 45 min later (TE2) after heating mode operation started.
• When the indoor pipe temp is 41°C or above, defrost control is not carried out even if the condition is one of the
defrost conditions above.
• While in defrost control, the compressor is on and the indoor fan, the outdoor fan, and the 4 way valve are off.
The outdoor
piping Temp.
12 C OFF
-6 C ON
INDOOR FAN
COMPRESSOR
4-WAY VALVE
9. Self-diagnosis Function
• 'CHECK' will flash in the remote controller display when a problem occurs.
• Correct the (fault messages) as shown in the table below before restarting operation.
• During the normal operation 'CHECK' won't be displayed in the remote controller.
Remote controller LCD
CH 01
CH 02
CH 03
CH 04
More than 45 minutes
of heating operation
ON
ON
FAULT MESSAGES
Indoor room temperature thermistor error
Indoor piping thermistor error
Indoor main body / Remote controller unit communication error
Water level float switch error
–19–
Within
More than 45 minutes
9min. 45sec.
of heating operation
More than 10 min.
running of compressor
HOT-
START
OFF
ON
OFF
ON
ON