Changing the game
The advent of variable-speed pump technology has changed the way water features are designed. In terms of saving time, using a variable-speed pump takes the guesswork out of pump sizing and, to a certain extent, line sizing. A well-designed variable-speed pump will provide the right amount of flow on windy days or calm ones; at the beginning, middle and end of the filter cycle; and whether or not the system has large-diameter pipe.
When using a standard pump, one can only hope the conditions, which were assumed when sizing the pump, hold true most of the time. Many designers have seen laminars and negative edges look perfect one week and wimpy the next, almost as if there isn’t enough water. This is completely understandable if the pump is always running at the same speed.
A pool system naturally builds up head pressure as the filter does its job between cleanings. Normal pumps have no choice but to continue trying to flood the edge at their set speed. Some variable-speed pumps, however, have the capability to measure flow automatically, respond to the naturally increasing system resistance and increase speed to maintain the required flow for the water feature.
The first time a variable-speed pump is used there may be a short learning curve with respect to programming the proper settings; however, most are quite easy to figure out.
Another advantage, with respect to water features, is the ability to vary the effect. For example, a pool owner may want to show off the full cascading rapids of a waterfall when guests first arrive for a party, but dial down the look and sound later in the evening. Similarly, a family may want a louder, more boisterous effect for a children’s party than an elegant poolside soirée. With a variable-speed pump and well-designed automation controls, it is possible to program these effects to automatically turn on at specific times. It is also possible to push a button on a remote control and make flow adjustments as easily as using a dimmer switch for a light.
In essence, the possibilities for water features are truly endless—so long as the hydraulic design is technically sound and the design takes advantage of the latest technology.
Phil Bach is the senior sales manager for Pentair Water Pool and Spa in eastern and central Canada. He has been working in the pool industry since 1978, starting as a pool service technician. Bach joined SwimQuip in 1988 and stayed with the company as it became Sta-Rite and then Pentair Water Pool and Spa.
