The swimming pool pump is the heart of the pool system. Just like an engine of a motor vehicle, the pool pump is the key component of the pool and spa filtration process.
In simple terms, a pool pump comprises an ‘electric motor’ and the ‘wet end’; the motor is sealed from the wet end by a ceramic seal. Most pool pumps are self-priming centrifugal with a vacuum chamber generally known as the pump housing. The pump housing must be filled with water to create the required vacuum to enable the pump to draw water from the pool or spa. The pump housing will remain full of water while the pump is operating and should remain full or part full when the pump is not operating.
When the pump is started the motor will begin to rotate; the pump motor spins the impeller located inside the pump volute. The ends of the impeller are hydraulically sealed inside the pump diffuser that enables the self-priming. Self-priming can only occur if the pump has a diffuser that helps to eliminate any air entering the pump housing from the suction supply.
A pump’s performance in regards to litres per minute will vary depending on the pump’s horsepower, pipe size, distance from the pool and restrictions in the system that the pump must overcome, such as filtration and sanitising equipment.
In a residential application, it’s often left to the pool builder to design the appropriate hydraulic set-up of any new pool and/or spa. The construction or renovation of a commercial pool requires the expertise of an engineer to configure the hydraulics.
In any case, it is important to identify the required ‘flow rates’ that will enable the pool’s filtration and sanitisation system to work correctly and to calculate the ‘total head’ of the pool’s hydraulic system.
When sizing a pool pump for a new or existing pool, there are several factors to consider such as, turnover time, the surface area, average depth, pool volume, turnover time, flow rate and head loss. These ensure the circulation system operates efficiently.