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12.5 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 233.6°F, compressor will be stopped, occurs 4 times per 20
minutes, timer LED will be blinking. “F97” is indicated.
12.6 Low Pressure Protection Control (Gas Leakage Detection)
• Control start conditions
o For 5 minutes, the compressor continously operates and outdoor total current is between 0.81A and 1.23A.
o During Cooling and Soft Dry operation:
Indoor suction temperature – indoor piping temperature is below 7.2°F
• Control contents
o Compressor stops (and restart after 3 minutes).
o If the conditions above happened 2 times within 20 minutes, the unit will:
Stop operation
Timer LED blinks and “F91” indicated.
12.7 Low Frequency Protection Control 1
• When the compressor operates at frequency lower than 25Hz continued for 240 minutes, the operation frequency
will be change to 24Hz for 2 minutes.
12.8 Low Frequency Protection Control 2
• When all below conditions comply, minimum limit of compressor frequency will be set.
Temperature, T, for: Cooling / Soft Dry
Indoor intake air (°F) T < 57.2 or ≥ 86
Outdoor air (°F) T < 55.4 or T ≥ 100.4
Indoor heat exchanger (°F) T < 86
12.9 Outdoor Air Temperature Control
• The compressor operating frequency is regulated in accordance to the outdoor air temperature as shown in the
diagram below.
• This control will begin 1 minute after the compressor starts.
• Compressor frequency will adjust based on outdoor air temperature.
Free
Limited Frequency
Outdoor air temperature
100.4°F or 77°F
98.6°F or 71.6°F