Panasonic CU-E18DBE Service Manual page 27

8.2.1.5. Compressor Overheating Prevention Control
Instructed frequency for compressor operation will be regulated by compressor discharge temperature. The changes of frequency
are as below figure.
8.2.1.6. Low Pressure Prevention Control (Gas Leakage Detection)
a. Control start conditions
Control will perform when (1) - (3) condition continues operation for 5 minute and (4) is fulfill.
1. During cooling and dry operation: Frequency more than normal Fcmax 78 Hz (E15D), 86 Hz (E18D).
During heating operation: Frequency more than normal Fh 71 Hz (E15D), 86 Hz (E18D).
2. Outdoor total current I cooling: Ib I Ia
Heating: Ib I Ic
Ic = Ia = 1.65 A
Ib = 0.65 A
3. It is not during deice operation.
4. During cooling and dry operation: indoor suction-indoor piping temperature is below 4°C.
During of heating operation: Indoor piping temperature-indoor suction is under 5°C.
Control contents:
• compressor stops (restart after 3 minutes)
• if happen 2 times within (20 minutes), perform the following operation
1) Unit stop operation
2) Timer LED blink and "F91" indicated
8.2.1.7. Low Frequency Protection Control 1
When the compressor operate at frequency lower than 25 Hz continued for 20 minutes, the operation frequency will be increased
to 24 Hz for two minutes.
8.2.1.8. Low Frequency Protection Control 2
When all the below conditions occur, minimum value (Freq. MIN) for the frequency instructed to compressor will change to 30 Hz
for cooling mode operation and 20 Hz for heating mode operation.
Temperature, T, for:
Indoor intake air (°C)
Outdoor air (°C)
Indoor heat exchanger (°C)
Cooling/Soft Dry
T 14 or T 30
T 13 or T 38
T 30
27
CS-E15DD3EW CU-E15DBE / CS-E18DD3EW CU-E18DBE
Heating
T 14 or T 28
T 4 or T 24
T 0