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14.1.5 Compressor Overheating Prevention Control

Instructed frequency for compressor operation will be regulated by compressor discharge temperature. The
changes of frequency are as below.
If compressor discharge temperature exceeds 224.6°F, compressor will be stopped, occurs 4 times per 20
minutes, timer LED will be blinking. (“F97” is indicated.)

14.1.6 Low Pressure Prevention Control (Gas Leakage Detection)

Control start conditions
o For 5 minutes, the compressor continuously operates and outdoor total current is between 0.64A and 0.85A.
o During Cooling and Soft Dry operations:
Indoor suction temperature - indoor piping temperature is below 39.2.°F.
o During Heating operations:
Indoor piping temperature - indoor suction is under 41°F.
Control contents
o Compressor stops (and restart after 3 minutes).
o If the conditions above happen 2 times within 20 minutes, the unit will:
Stop operation
Timer LED blinks and “F91” indicated.

14.1.7 Low Frequency Protection Control 1

When the compressor operates at frequency lower than 24Hz continued for 240 minutes, the operation frequency
will be changed to 25Hz for 2 minutes.

14.1.8 Low Frequency Protection Control 2

When all below conditions comply, minimum limit of compressor will be set.
Temperature, T, for: Cooling / Soft Dry Heating
Indoor intake air (°F) T < 57.2 or T 86 -
Outdoor air (°F) T < 55.4 or T 100.4 T < 57.2 or T 82.4
Indoor heat exchanger (°F) T < 86 T 32

14.2 Protection Control For Cooling & Soft Dry Operation

14.2.1 Outdoor Air Temperature Control

The maximum current value is regulated when the outdoor air temperature rise above 57.2°F in order to avoid
compressor overloading.