Panasonic CS-Z25UD3EAW Service Manual page 84

16.1.4 Compressor Overheating Prevention Control

Instructed frequency for compressor operation will be regulated by compressor temperature. The changes of
frequency are as below.

If compressor temperature exceeds 103°C, compressor will be stopped, occurs 4 times per 20 minutes
("F97" is indicated.)
16.1.5 Low Pressure Prevention Control (Gas Leakage Detection)

Control start conditions
For 5 minutes, the compressor continuously operates and outdoor total current is between 0.75A and 0.95A
o
(Z25/35UB4), 1.38A and 1.65A (Z50/60UB4).
During Cooling and Soft Dry operations:
o
Indoor suction temperature - indoor piping temperature is below 4°C.
During Heating operations :
o
Indoor piping temperature - indoor suction is under 5°C.

Control contents
Compressor stops (and restart after 3 minutes).
o
If the conditions above happen 2 times within 20 minutes, the unit will:
o
 Stop operation
 "F91" indicated.
16.1.6 Low Frequency Protection Control 1

When the compressor operate at frequency lower than 24 Hz continued for 20 minutes, the operation frequency
will be changed to 23 Hz for 2 minutes.
16.1.7 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)
103°C
99°C
96°C
Comp. temperature
Temperature, T, for:
Compressor = OFF
88°C
Compressor Frequency
Reduce
87°C
Compressor Frequency
Maintain
86°C
Free
Cooling/Soft Dry
T < 14 or T ≥ 30
T < 13 or T ≥ 38
T < 30
84
Heating
T < 14 or T ≥ 28
T < 4 or T ≥ 24
T ≥ 0