public HeaterViewModel()
 {
     LiquidVM        = new LiquidViewModel();
     ElectricalVM    = new ElectricalViewModel();
     ExtraLiquid     = new LiquidViewModel();
     ExtraElectrical = new ElectricalViewModel();
     HeaterList      = Heater.GetHeater();
     ExtraHeaterList = Heater.GetHeater();
     PageViewHeaterModels.Add(new EmptyVM());
     PageViewHeaterModels.Add(LiquidVM);
     PageViewHeaterModels.Add(ElectricalVM);
     PageViewExtraHeaterModels.Add(new EmptyVM());
     PageViewExtraHeaterModels.Add(ExtraLiquid);
     PageViewExtraHeaterModels.Add(ExtraElectrical);
     CurrentPageExtraHeaterViewModel = PageViewExtraHeaterModels[0];
     CurrentPageHeaterViewModel      = PageViewHeaterModels[0];
     SelectedValueHeaterVar          = HeaterList[0];
     ExtraHeater = false;
 }