Used in both XT10/XT10I and XT15/XT15I. The X78 Flow Control Assembly is used to visually indicate that water is flowing through the reflux circuit during the reflux cycle. Once the solvent has reached extraction temperature, the reflux circuit will cycle on and off.  

When on, a red light on the control panel will illuminate, the reflux water valve will turn on, and a float in the Flow Control Assembly will rise to a level between 2-7 (we recommend a level of 4 or more if you are using a chiller water supply of 15°C or less,  or a level of 5 or more if you are using a lab water supply of 23°C or less). 

When the reflux circuit is on, the control knob can be used to adjust the flow, but it is factory set and not normally adjusted.