Protection Control For Heating Operation - Panasonic WH-MHF12G9E8 Service Manual

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.

Deice judging condition
Outdoor Unit Deice Control
10
5
0
-5
-10
-15
-20
-25
-30
-30 -20

Deice operation time diagram
a. Deice mode 1 control:
Free
Compressor
Four way valve
ID pump
OD fan
Expansion valve
Free
-10 0
Outdoor Temperature (°C)
1 2 3
ON
ON
Free
When Heating Time > 35 minutes
and Pipe Temperature below this
line for continuous 3 minutes
10 20
5
4
OFF
ON
OFF
max 9 minutes 30 seconds
deice 1
78
Deice start depends:
1. Outdoor air sensor temp.
2. Outdoor pipe sensor temp.
3. Heating accumulation time
30
8
6 7
ON
ON
Free
Free
9