Protection Control For Heating Operation - Panasonic WH-UD07CE5-A Service Manual

14.1.7. Low Frequency Protection Control 2
• When all the below conditions comply, the compressor frequency will change to lower frequency.
14.1.8. 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).
14.1.9. Outside Temperature Current Control
14.1.10. Crank case heater control
• Purpose:
- For compressor protection during low outdoor ambient operation (during heating low temperature operation).
• Control content:
a. Trigger heater START conditon
• when the outdoor air temperature is 4°C or below, and discharge temperature is 11.6°C or below.
b. Resetting heater STOP condition
1. when the outdoor air temperature exceeds entry condition (6°C)
2. when the discharge temperature exceeds entry condition (18.8°C)

14.2. Protection Control For Heating Operation

14.2.1. 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.
14.2.2. Deice Operation
When outdoor pipe temperature and outdoor air temperature is low, deice operation start where outdoor fan motor stop.
Temperature, T, for:
Outlet water (°C)
Outdoor air (°C)
Indoor heat exchanger (°C)
Heating
T < 14 or T 48
T < 4 or T 24
T 0
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