Defrost Control - LG AH-W096A0 Service Manual

7. Defrost Control

7.1 Function
:These are controls of compressor, fan of outdoor unit, reversing valve, and EEV..
7.2 Starting to the defrosting operation
A) Defrost operation will be started when all the conditions below are matched simultaneously
Accumulation time of operation and the period after completion of defrost = 35min (Outdoor air temperature –3˚C)
B) Outdoor piping temperature is below than –6 (Option)˚C for starting defrosting operation.
7.3 Completion of defrost operation
Send signal of defrost completion in case of meeting one of the condition as below.
1. Defrosting time ≥ 7 minutes
2. Piping temperature maintain 10 seconds (Option ) in condition of more than 12˚C (Option).
7.4 Defrosting Control Algorithm
Control
Inverter Comp.
Control
Outdoor EEV
Reversing Valve
Hot gas bypass
(Option)
Bypass valve
Indoor Fan
Outdoor Fan
Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Satisfy
Defrost
Defrost
Start
Start
Condition
1 2 3
80 Hz
45 Hz
350 Pulse
Defrost signal of indoor unit on/
Starting maximum defrosting
time count
ON
OFF
OFF
Fan ON when pipe temperature
ON
Satisfy
Heating
Defrost
Start
End
(Defrost flag clear)
Condition
4 5 6 7
(Option)
(Option)
(Option)
Indoor defrost signal OFF
OFF
ON
ON
OFF
above 25°C(option)
Maximum flow
OFF
- 38 -
Control logic
8 9 10 11
Baseline
Step E
Step D
Step C
ON
OFF
OFF
Hot
start
ON/OFF
Setting flow
LGE Internal Use Only