For 32 years, the voice of the pool and spa service professional.

Getting to the heart of the matter

By Marcelle Dibrell

The heart of the circulation system is the pump, whose job it is to move water. 

Similar to an animal’s beating heart moving blood to all parts of the body, the pool pump’s purpose is to circulate water throughout all parts of the pool. 

Without a means of water circulation and filtration, swimming pools would be bathtubs, containing all of the bather waste accumulated over time, with no means of removal except draining. 

Swimming pools must be circulated continuously to provide healthy, clean water, and the pump is what makes it happen.

The pumps in use today include single-speed, dual-speed and variable-speed capabilities.

The first motor-driven pumps used to circulate pool water became available in the early 1900s. 

However, despite the fact that water pump technology existed even as late as the 1920s, there were no pumps or filter devices designed for use with residential pools. 

Instead, contractors usually adapted pumps from the marine industry. Most pools were simply drained and refilled.

Pumps have been powered by single- speed technology until quite recently. 

The first circulator pump to be placed on the market with variable-speed technology occurred in 1962 by the manufacturer Grundfos. 

This pump was presented for central heating circulation as well circulation of domestic hot water. 

However, it wasn’t until 2005 that variable-speed pumps became available to the pool and spa industry, first introduced to the public by Pentair. 

Variable-speed pumps are marvels of efficiency. 

Because pool pumps are called upon to perform a variety of operations, they must be sized to perform the most demanding task, which may include running the filter or pool cleaner, operating jets or fountains, and running a solar heater.

Single-speed pumps, by definition, cannot change their flow rates. 

That means that for normal filtration purposes, the primary function of the pump, they are providing far greater circulation than the filtration system needs. 

Dual-speed and variable-speed pumps, on the other hand, can be adjusted to operate at lower flow rates during normal filtration, which significantly lowers the energy usage, thus saving money.

Variable-speed pumps offer an important advantage over their dual-speed counterparts, however. In many cases, the lower speed on a dual-speed pump is not sufficient for normal filtration, so the pump is always operated at its higher speed, negating any energy savings.

At the end of the day, variable-speed pumps produce better water quality because water can be circulated at all times. Moving water means clean water, and since circulation is achieved at the lowest speed possible, they still save electricity.

Variable-speed pumps save energy for two basic reasons. First, less power is consumed when the water is moved slowly. Second, because variable-speed pumps use permanent-magnetic motors rather than induction motors, there is no energy loss due to rotor resistance, which improves their efficiency.

Paid subscribers have full access to the complete coverage on pool and spa pumps. Contact our circulation department at 949-916-0292 or email for details.

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