Panasonic CS-YE18NKV-6 Service Manual page 41

13.1.4 Compressor Overheating Prevention Control
Instructed frequency for compressor operation will be regulated by compressor top temperature. The changes of
frequency are as below figure.
If compressor discharge temperature exceeds 107°C (YE18NK) and 112°C (YE24NK), compressor will be stop,
occurs 4 times per 20 minutes, timer LED will be blinking ("F97" is to be confirmed).
13.1.5 Low Pressure Prevention Control (Gas Leakage Detection)
A. Control start conditions

For 5 minutes, the compressor continuously operates and outdoor total current is between 1.38A and 1.65A
(YE18NK only).

For 5 minutes, the compressor continuously operates and outdoor total current is between 1.88A and 2.85A
(Cooling), 2.85A and 3.57A (Heating) (YE24NK only).

During Cooling operations:
Indoor suction temperature - indoor piping temperature is below 4°C.

During Heating operations :
Indoor piping temperature - indoor suction is under 5°C.
B. Control contents

Compressor stops (and restart after 3 minutes).

If the conditions above happen 2 times within 20 minutes, the unit will:
Stop operation
o
Timer LED blinks and "F91" indicated.
o
13.1.6 Low Frequency Protection Control 1

When the compressor operate at frequency lower than 24 Hz (YE18NK) and 20 Hz (YE24NK) continued for 20
minutes, the operation frequency will be changed to 23 Hz (YE18NK) and 21 Hz (YE24NK) for 2 minutes.
13.1.7 Low Frequency Protection Control 2

When all the below conditions comply, the compressor frequency will change to lower frequency.
Indoor intake air (°C)
Outdoor air (°C)
Indoor heat exchanger (°C)
Temperature, T, for: Cooling
T < 14 or T 30
T < 13 or T 38
T < 30
41
Heating
T < 14 or T 28
T < 4 or T 24
T 0