SiEBE18-526 Basic ControlFunction 592.3 Electronic Expansion Valve PI ControlMain Electronic Expansion Valve EV1 ControlCarries out the electronic expansion valve (Y1E) PI control to maintain the evaporator outletsuperheated degree (SH) at constant during heating operation to make maximum use of theoutdoor unit heat exchanger (evaporator).The optimum initial value of the evaporator outlet superheated degree is 5°C, but variesdepending on the discharge pipe superheated degree of inverter compressor.Subcooling Electronic Expansion Valve EV2 ControlMakes PI control of the electronic expansion valve (Y2E) to keep the superheated degree (SH)of the outlet gas pipe on the evaporator side for the full use of the subcooling heat exchanger.SH = Ts - Te SH : Evaporator outlet superheated degree (°C)Ts : Suction pipe temperature detected by thermistorR2T (°C)Te : Low pressure equivalent saturation temperature(°C)SH = Tsh -Te SH : Outlet superheated degree of evaporator (°C)Tsh : Suction pipe temperature detected with thethermistor R5T (°C)Te : Low pressure equivalent saturation temperature(°C)
