Water Distribution Grade 1 Certification Practice Exam

What must be provided on the suction piping to hold the prime if a centrifugal pump is located above the level of water?

1. Foot Valve

2. Check Valve

3. Pressure Relief Valve

4. Ball Valve

The correct answer is: Foot Valve

The correct answer is a foot valve because it serves a critical purpose in maintaining the prime of a centrifugal pump located above the water source. A foot valve is a type of check valve installed at the pump's suction line, positioned below the water level. Its main function is to prevent backflow and ensure that the liquid remains in the suction line when the pump is not operational. By doing so, it holds the prime in the system, which is essential for the pump to be able to function properly when started again. In the context of centrifugal pumps, losing the prime can lead to cavitation and damage to the pump. With a foot valve in place, even if the pump is not running, the water in the suction line remains in place, ready for immediate use once the pump is activated. This is particularly important for pumps that are installed above the water source, as gravity alone cannot keep the water in the suction line without such a valve. Other options such as a check valve, pressure relief valve, and ball valve serve different purposes in water distribution systems. A check valve prevents backflow but may not maintain a prime. A pressure relief valve is designed to manage pressure levels in the system, protecting against overpressure scenarios. A ball valve provides a