Solar Heating Settings-Aqualink RS One Touch

I have the above system with solar heating. I understand from others there is a setting for the controller for solar heating. It sets how much a differential is allowed between the water temperature and the solar temperature before the system turns off the flow from the solar panels. Supposedly the differential is six degrees which is not acceptable for my operation and I want to change it.

Can not find any mention of this function in my manual.

Anyone familiar with this setting?

Thanks,

John