As embarrassing as it is to say ...since I put in the oil burner 15 years ago .. I don't know how it works .. but I have two switches feeding the relay box then the burner.. one seems to control the pumps and one the burner. Under the cover on my burner itself is a dial just like on the aqua stat on my OWB .. just turned that down also. In my system I have regular 50 gallon hot water tank that instead of a gas burner or electric coil there is one of the oil burner zones feeding it. It has its own aqua stat set at 110 degrees .. turns on that pump when the water in the tank drops below that and turns the pump off at 120. hope that made sense