Panasonic WH-MDF12C6E5, Service Manual

Page: 63 / 121

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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
o
When the outdoor air temperature is 4°C or below, and discharge temperature is 12°C or below.
b. Resetting heater STOP condition
1.
when the outdoor air temperature 6°C.
2.
when the discharge temperature 19°C.
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 Deice Operation
When outdoor pipe temperature and outdoor air temperature is low, deice operation start where outdoor fan motor
stop.
13.2.3 Heat-exchanger (hot water coil) protection control
Backup heater ON condition:-
o
water inlet temperature < 23°C AND
o
outdoor ambient temperature < 10°C
Backup heater OFF condition:-
o
water inlet temperature > 25°C OR
o
outdoor ambient temperature > 13°C