Hello, I ran into a fafco ac 600 which is a semi automatic control for the pool solar. On the bottom end It has 3 tubes that run from the suction side, pressure side, and to a bladder inside the bypass. And 3 tubes going to the roof under a black dome which I assessed is some kind of sensor. I understand how it works on the bottom end to control the bladder but how do the three tubes going to the roof work?? What is it doing? Thank you