turning on 3 way Jandy valve for solar heating

[binbino]

Hi, the installer of my solar system shut the valve to "OFF" during the winter to make sure solar system is disabled and now I'm trying to turn it back on. I found there are two ON switches, "ON 1" and "ON 2". What are their differences and which one should I use?

Thanks

 

[kadavis]

The two switches determine what direction the valve will turn, either clockwise or counterclockwise. Try one and see which way it turns and if it coincides when the solar is supposed to be on then leave it