What is needed at the bottom of a pipe when the pump is above water?

A foot valve is essential at the bottom of a pipe when the pump is positioned above the water source. Its primary function is to maintain a prime in the suction line by preventing backflow when the pump is turned off. This ensures that the pump remains filled with liquid, allowing it to effectively draw water when operating.

When situated above water, the pump relies on the foot valve to create the necessary suction to pull water up into the system. Without this valve, water could drain back down the line when the pump is not running, leading to issues such as loss of prime, which can prevent the pump from functioning properly during subsequent operational cycles. Thus, using a foot valve is critical for the effectiveness and efficiency of the pumping system in this configuration.