Electronic Refrigerant Control Valve Control - Sanyo SPW-X253GH56 Service Manual

2-19 Electronic Refrigerant Control Valve Control

The circulation volume of the refrigerant is controlled by a pulse type electronic control
valve.
When the power is switched ON, the opening degree of the electronic control valve is
controlled between 90 and 480 steps after setting the initial step at the time when the
thermostat is ON.
Contents and Order of control
Discharge gas temperature control
Outdoor unit coil temperature control
Freeze prevention control
Refrigerant flow distribution control
Discharge gas target temperature
control (Fuzzy control)
* Repeat control in accordance with the priority order.
Even though the operation is performed every 30 seconds, the control of discharge gas
temperature, high load prevention, outdoor unit coil temperature and freeze prevention
activates when it occurs.
(1) Refrigerant flow distribution control
At the control of flexible combination (a plural number of indoor units are set), the opening
degree of the electronic control valve is controlled by the indoor unit coil temperature.
Cooling: indoor unit coil E2 temperature (located at the middle of coil)
Heating: indoor unit coil E1 temperature (located at the outlet of coil)
(2) Fuzzy control (optimal refrigerant flow rate control)
By outputting the fuzzy estimation result corresponding to the fuzzy input variables (the
indoor unit coil temp., the deviation between the actual discharge gas temp. and the target
discharge gas temperature calculated from the outdoor unit coil temperature and the
change thereof), the electronic refrigerant valve is controlled so that the unit can perform
its maximum ability in accordance with the indoor and outdoor temperature conditions at
the operation.
Cooling
Start
*
– 43 –
2. Processes and functions
Heating
Start
Discharge gas temperature control
High load prevention control
Heating start up control
Refrigerant flow distribution control
Discharge gas target temperature
control (Fuzzy control)
*
0451_M_S
SM830033
2