Special Control; Defrost Control - LG AVNH-EL Service Manual

2. Special control

2.1 Defrost control

: In case the temperature of the outdoor unit heat exchanger falls continuously this function will prevent heat
exchanger from freezing.
2.1.1 Defrost PROCESS Starting conditions
1) Only Operates in the heating mode.
2) The defrost timer (The first time : outdoor unit is turned on ,the minimum for defrost operation to start is
over 45~120 minutes.
3) The compressor operates continuously for over ten minutes
4) Outdoor pope maintains a temperature of below -5°C for 4 minutes . (If the time of accumulated defrost
operation is over 90 minutes, maintain below -3°C)
5) When the above 1)~4) conditions be satisfied, Defrost operation will be start.
2.1.2 Defrost cycle time
1) Defrost process starting conditions is decided after 45(30)~120min. according to the outdoor Temp.
2) Defrost process stop conditions is decided after 4min.
3) Defrost process stops at maximum 9 min.
2.1.3 Defrost PROCESS
1) The previous situation of outdoor unit maintains for 20 second just before changing defrost control.
2) The LEV phase of indoor unit open to the 500 phase(=full open)
4) Changing the cooling mode of 4WAY VALVE ¡ Direct the fan of indoor unit to stop. (4WAY VALVE is
operated to convert the process to cooling irrespective of the cycle's start/stop.
5) Stand by for 5 second.
6) The FAN of outdoor unit is OFF
7) Defrost PROCESS starts.
8) If the pipe Temp.of outdoor unit is above 12°C in Defrost mode, operate the fan of outdoor_unit.
If it is under 8°C in Defrost mode, stop the fan of outdoor_unit. if it is between 9°C and 11°C, the out-
door_unit maintains the previous situation.
9) Defrost PROCESS stop conditions
¡ Pipe temperature of the outdoor_unit is above 12°C for 150 minutes or defrosting operation starts after
6~9 minutes.
10) When these conditions be satisfied,Defrost operation will be maintained for 20 seconds
11) LEV initialization, the FAN of outdoor unit is ON, 4WAY_VALVE switched to heating mode, the FAN of
indoor_unit stops the OFF situation.
12) Defrost PROCESS complete.
*. 8), 9) conditions is only applied to continuous operating CYCLE.
Outdoor Units
Service Manual 133