Speed
Historically, pumps with induction motors, which operate at only one or two speeds, have drawn more energy than is required to circulate pool water. These units must constantly operate at high speed to perform demanding jobs, such as running a waterfall or pool cleaner. However, it takes far less power to simply keep the pool water filtered—a difference single-speed pumps cannot address.
On the other hand, variable-speed pumps (VSPs) can be programmed to operate at set speeds to deliver the correct flow rate for each task they perform. This allows the pool’s pump to reduce energy consumption and ultimately reduce operating costs. These pumps can also be programmed to achieve turnover times of exactly six hours, even if the filter is dirty. This allows motor speed, power, and energy to be reduced during times when filters are clean, instead of sizing the pump to assume worst-case operating conditions.
Some VSPs have built-in constant-flow software, which maximizes the advantages these pumps have, as it will automatically adjust its speed to deliver the required flow rate for each programmed task. For instance, if an arcing laminar water feature requires 151 lpm (40 gpm) to produce a smooth 1.8-m (6-ft) arc of water, the pump will automatically ramp up its speed when it senses resistance in the circulation system (e.g. as the filter accumulates dirt) to continually provide the proper flow rate. With other pump types, the water feature will gradually throw a shorter arc of water as the filter gets dirtier.
No matter what type of pump is being used, however, slower pump speeds save energy. Slower speeds also dramatically reduce noise levels and wear and tear on the other pool equipment the water flows through.
Mike Fowler is the commercial marketing/sales for Pentair Commercial Aquatics in Sanford, N.C. He has been with Pentair since 1992, starting his career in the technical services department at Purex Pool Products. Fowler has held many managerial roles within the company, including marketing, accounting and products. He can be reached via e-mail at mike.fowler@pentair.com.
