4-4 Freeze Prevention (Cooling)
Freeze Prevention keeps the indoor heat exchange coil from freezing. Freezing reduces the efficiency of the
unit, and frost build up on the coil blocks cool air circulation from the indoor unit's fan.
Note:
Freeze prevention is controlled by the temperature at the indoor heat exchanger coil as sensed by
either sensor E1 (located at the entrance of the coil) or sensor E2 (located on the middle of the coil).
Freeze prevention cycle is controlled by the lower temperature sensed at either of the two sensors.
This chart shows when the electronic expansion valve opens to regulate the temperature of the indoor unit
coil to prevent freezing.
If the refrigerant control is not effective and the temperature continues to drop and stays below 0°C for 2
minutes continuously, the control circuit stops the compressor. The compressor does not start again until
the temperature rises above 1°C. The compressor stops for 3 minutes minimum.
Note:
• When low fan speed is selected and the air conditioner is in cooling operation at a low outdoor
temperature of less than 10°C, the air conditioner may automatically switch to medium fan
speed.
• Cut the jumper wire (JP11) on the outdoor P.C.B. when the above FMI control (L M) is not
needed.
Chart Explanations and notes
Fig. 8
(°C)
INDOOR UNIT
COIL TEMP.
ELECTRONIC
EXPANSION
VALVE SIGNAL
MIN. VALUE OF
EITHER E1 OR E2
1
3
-0.5
0
-0.5
COMPRESSOR
CONTINUOUS
DETECTION
FOR 2 MINUTES
ON
ON
1563_M_S
FMI CONTROL
L M
L M
17
