Electronic Expansion Valve Control - Fujitsu AUXB04GALH Service Manual

3-4-1 ELECTRONIC EXPANSION VALVE CONTROL

1. Initialization
When the power is turned ON.
When it has passed the limited time since the last initialization.
2. Operation Control
When indoor unit stopping
Outdoor unit Condition
OFF
Cooling
Heating
When starting up
(Cooling) Move to the cooling control base pulse in steps.
(Heating) Move to the heating control base pulse in steps.
Automatic operatic control
Automatic PI control is performed based on the indoor unit heat exchanger outlet temp and inlet temp.
Room temperature control
The room temperature is controlled so that it reaches to the set-up temperature based on the difference
between the room temperature and the set-up temperature, and the change of indoor unit temperature.
if the room temperature becomes 0.5 C lower than the set-up temperature, EEV is fully closed.
3. Special Control
Oil recovery operation : Controlled pulse.
Test run operation
Icing protection control : Fully closed.
Pump down operation : Fully open.
Defrost operation
EEV Condition
Fully closed
Fully closed
Slightly open
: Controlled pulse.
: Controlled pulse
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