SL1629-NH2 fresh air heat pump controller controls two compressor systems, with internal main circuit and external main circuit electronic expansion valve control; 
the number of optional accessories is the maximum number required by each control board, which can be selected according to the actual model. 
the display screen will display a 10-second welcome page when it is powered on. this welcome page displays the current unit information and text screen version number information. Press any key on the welcome page to exit the welcome page and enter the main page.