Panasonic WH-UD28AE, Service Manual

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13.1.7. Low Frequency Protection Control 2
• When all the below conditions comply, the compressor frequency will change to lower frequency.
13.1.8. Low 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.
- Error H63 will be displayed.
13.1.9. 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.
- Error H64 will be displayed.
13.2. Protection Control For Heating Operation
13.2.1. Outdoor Air Temperature Control
The maximum current value is regulated when the outdoor air temperature rises above 14
°
C in order to avoid compressor
overloading.
13.2.2. Overload Protection Control
The compressor operating frequency is regulated in accordance to indoor heat exchanger temperature as shown in below figures.
13.2.3. Deice Operation
When outdoor pipe temperature and outdoor air temperature is low, deice operation start where outdoor fan motor stop.
Temperature, T, for: Heating
Outlet water (
°
C)
T < 14 or T 48
Outdoor air (
°
C)
T < 4 or T 24
Indoor heat exchanger (
°
C)
T 0