What component maintains the day tanks at the correct level without overflowing them?

Float valves are designed specifically to maintain water levels in tanks, including day tanks, by automatically controlling the inflow of water. These valves operate based on the principle of buoyancy, where a float rises or falls with the water level. When the water level reaches a predetermined height, the float triggers the valve to close, stopping additional water from entering the tank. This mechanism effectively prevents overflow while ensuring that the tank remains filled to the desired level.

In contrast, pressure regulators are used to maintain a set pressure within a system, not specifically to monitor or control liquid levels. Check valves allow fluid to flow in one direction and prevent backflow, without any role in level maintenance. Level sensors, while capable of detecting fluid levels, require additional components to actually control inflow, which is not their primary function. Thus, float valves are the appropriate component for maintaining the correct level in day tanks, preventing overflow and ensuring proper operation.