Panasonic WH-MHF09G3E8, Service Manual

Page: 68 / 140

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12.13 Anti Freeze Control

Anti freeze protection control menu can be set YES or NO by control panel.

In heatpump system, there are 3 types of anti freeze control:
1. Expansion tank anti-freeze control
 Expansion tank anti freeze heater ON condition:
o
Outdoor ambient temp. < 3°C
 Expansion tank anti freeze heater OFF condition:
o
Outdoor ambient temp. > 4°C
2. Water pump circulation anti freeze control
 Water pump turns ON when ALL below conditions are fulfilled:
o
Heatpump OFF (stand by) OR error occurs.
o
Water flowing flag is ON.
o
Water flow switch is not abnormal.
o
Outdoor ambient temp. < 3°C OR outdoor ambient temp. sensor is abnormal.
o
Water inlet/outlet temp. < 6°C.
o
After 5 minutes from previous water pump OFF.
 Water pump turn OFF when ANY of below conditions is fulfilled:
o
Outdoor ambient temperature ≥ 4°C.
o
During -5°C < outdoor ambient temp. < 4°C
 After water pump ON for 4 minutes, and water inlet temp. ≥ 8°C.
 Else, shift to back up heater anti freeze control.
o
During outdoor ambient temp. < -5°C

After water pump ON for 4 minutes, and water inlet/outlet ≥ 20°C.
 Else, shift to back up heater anti freeze control.
 However, if flow switch is abnormal (H62), then water pump circulation anti freeze control will not activate.
3. Back up heater anti freeze control:
 Back up heater turn ON when ALL below conditions is fulfilled:
o
Water inlet/outlet temp. < 6°C.
o
Water pump circulation anti freeze control activated and water pump ON for 4 minutes.
 Back up heater turns OFF when ANY of below conditions is fulfilled:
o
Water inlet/outlet temp. > 28°C.
o
Water pump circulation anti freeze control deactivated/water pump OFF.
 However, if back up heater is abnormal (H70) then back up heater anti freeze control will not activate.