Panasonic WH-SDC09C3E8 Service Manual page 69

13.1.6 Low Frequency Protection Control 1

When the compressor continuously operates at frequency lower than 25 Hz for 240 minutes, the operation
frequency will change to 24 Hz for 2 minutes.
13.1.7 Low Frequency Protection Control 2

When all the below conditions comply, the minimum compressor frequency will change to lower frequency.
Temperature, T, for:
Indoor heat exchanger (°C)
13.1.8 High Pressure Sensor Control

Purpose:
- To protect the system operation.

Detection period:
- After compressor on for 5 minutes.

Detection conditions:
- When abnormal high voltage detection, 5V or when open circuit detection 0V for 5 seconds continuously.

After detection:
- When abnormality is detected continue 5 seconds, unit stop operation.
- OFF/ON control panel LED will blink (H64 error occurs).
13.1.9 Outside Temperature Current Control
13.1.10 Crank Case Heater Control

Purpose:
- For compressor protection during low outdoor ambient operation (during heating low temperature operation).

Control content:
a. Trigger heater START condition
When the outdoor air temperature is 4°C or below, and discharge temperature is 11.6°C or below.
o
b. Resetting heater STOP condition
When the outdoor air temperature exceeds entry condition (6°C)
1.
When the discharge temperature exceeds entry condition (18.8°C)
2.
Outlet water (°C)
Outdoor air (°C)
Heating
T < 14 or T 48
T < 4 or T 24
T 0
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Cooling
T < 14 or T 30
T < 13 or T 38
T < 30