What is a check valve located on the suction side of a pump designed to maintain?

A check valve located on the suction side of a pump is designed to maintain the prime of the pump. Priming is essential for a pump to function correctly, as it prevents air from entering the pump's casing, which can lead to cavitation or loss of suction. By preventing backflow of water, the check valve ensures that the pump remains filled with liquid, allowing it to maintain its operational efficiency. This design helps to sustain the pump's ability to draw water, particularly during start-up after the pump has been turned off, thus ensuring a continuous and reliable flow of liquid when the pump is engaged.

In this context, the other choices do not align with the function of the check valve in terms of maintaining pump operation. Water temperature and clarity relate to the quality and condition of the water, while flow rate pertains to the volume of liquid moving through the system, which is not directly regulated by the check valve on the suction side.