To answer your questions, the factory default is 2 hours, twice per day and it is programmable to whatever. Did you add the dedicated circ pump or are you just going with the standard set up? If you added the dedicated circ I would probably just set it for continuous operation. With the low speed on pump (standard configuration) I usually recommend starting with 8 hours (total) per day and see how that works for you. After a couple of months you can adjust as needed.