The purpose of the water-level control is to automatically maintain proper water level in the ice flaker. Proper water level should be horizontal with the center of the AEV (See fig. 131b).
You must use high- and low-side pressure readings, water and air temperatures, the frost line, the sight glass, plus general conditions of cleanliness to assess the refrigeration system status when making any adjustments.
The location of the frost line can be very helpful in determining proper operation of the refrigeration system. The frost line is lowered by higher than normal water temperature or higher ambient air temperature and also poor refrigeration system efficiency. Ideally, the frost line should be seen on the flare nut attaching the evaporator to the heat exchanger, after the unit runs for at least fifty minutes, making ice flakes continually.
(See fig. 131a.)
To locate the frost line (1) remove the side panels, and (2) remove the black insulation over the flare nut and suction line by cutting it with a knife (save the insulation as it must be replaced). In dry areas where a frost line may not be visible, moisten the suction return line with a damp cloth to make it appear.
Turn the AEV adjustment screw clockwise to move the frost line toward the heat exchanger and raise the suction pressure. Turn the AEV adjustment screw counterclockwise to move the frost line toward the evaporator. (See fig. 131a.)