7
Defrost Function
2 ZONE
In HEAT mode if the outdoor coil temperature is very low and there is ice formed on the coil. The air conditioner cannot
operate efficiently and the compressor may be damaged. The defrost function will be activated, it will reverse the system‟s
mode operation from heat to cool. The heat will be transferred from the indoor unit to the outdoor coil. Meanwhile the indoor
fan will be stopped to protect the user in the room from the cold draught.
As soon as the outdoor coil temperature is below 3
o
C, the defrost timer starts. If the temperature is above 3
o
C more than 2
minutes, the timer is reset.
The defrost process is activated if
a) The compressor has been running continuously more than 5 minutes and the system is put in heat mode.
b) The defrost timer time meets one of the below conditions
The outdoor coil temperature is decreased from +3 to -8
o
C (line AB) during 30-60 minutes and remains at -
8
o
C or below, more than 5 minutes.
The outdoor coil temperature is reduced from +3 to -4
o
C (line AC) during 60-120 minutes and remains at
-4
o
C or below, more than 5 minutes.
The outdoor coil temperature is reduced from +3 to -2
o
C (line AD) after 120 minutes and remains at -2
o
C or
below, more than 5 minutes.
While the defrost function is activated,
The indoor fan stops and
The outdoor fan stops while the compressor runs and
The reversing valve is not energized (running in cool mode) and
The LED on the display unit blinks.
The system will go back to the normal stage if
The outdoor coil temperature is above 30
o
C or
The defrost function operates more than 10 minutes or
The air conditioner is turned off.
In COOL or DRY mode if the compressor has been operating more than 3 minutes but the indoor coil temperature is still
above 25
o
C, the compressor has failed. The controller will send the alarm by blinking LED on the display.
To exit is by turning off the air conditioner or changing the mode of operation of Fan or Heat.