Variable Speed Pumps
Variable Speed Pool Pumps
Pool pumps account for 70-90% of all electricity used to operate swimming pools. Pumps are sized according to the volume of water in the pool, the resistance of the plumbing and the design flow rate of the pool filter. Pool filter pressure of more than 5 psi indicates a fair amount of resistance that the pump must overcome.
In many cases, pool pumps are oversized to compensate for static and friction losses, as well as dirt load in baskets and filters. They are also often oversized to handle a range of duties in addition to filtration, including powering in-pool or in-floor cleaners, attached spas or water features.
Standard pool pumps spin the impeller at 3450 RPM all the time. Flow rate can be further controlled with bypass valves or throttling plugs in the skimmers. Increasing pipe diameter (to 2” PVC), or reducing plumbing turns will reduce resistance and resulting pressure in a pool system.
Variable speed pumps can select from a number of different speeds from to operate at most efficiently. The advantage of a lower speed is less energy required to do the pumping work. It also translates to less stress on pool equipment and plumbing, with a corresponding increased lifespan.
Variable Speed and Variable Flow Pool Pumps
Variable speed pumps such as the Hayward Superpump VS or Max-Flo VS are essentially fully programmable 3-speed pool pumps. The Hayward EcoStar is also a variable speed pump that offers 8 speed settings in a wider range, and will connect to pool controller systems easily.
The Pentair Intelliflo VF model however, is different. Variable Flow pool pumps can sense the pressure and adjust pump speed automatically to provide the correct speed for filtering, heating, cleaning or for using attached spas or water features. VF pumps automatically calculate and program the minimum flow requirements for any pool task, optimizing energy savings.
For most pools, a 3-speed variable speed pump would be sufficient. Larger pools with spas, waterfalls or in-floor cleaners could benefit from a variable flow pump, for convenience in set-up and operation, and greater energy savings.
Variable Speed Pumps with SVRS
SVRS stands for Safety Vacuum Release System. In pool pumps equipped with SVRS, the motor control monitors the vacuum pressure, and when it senses a blockage or obstruction from the suction side of the pump, it shuts off the pump motor. SVRS is designed to prevent entrapment injuries, by shutting off the pump if a person became suctioned to, or stuck into, a pool main drain or wall suction fitting.
The Virginia Graeme Baker Pool & Spa Safety Act of 2007 has mandated commercial pools to convert to dual main drain systems with safer drain covers, and/or install a SVRS on existing pool pumps. There are currently no such requirements for residential pools, however main drain safety is a valid concern for every pool owner.
Installing Variable Speed Pool Pumps
Installation of a variable speed pump is no different than installing a standard pool pump. There is some plumbing to be done, and some recommendations for pipe size and pipe length in front of the pump can be found in the installation manual.
VS pumps require 230V to operate and the wires connect in the same fashion as they do on a standard pump – two hot leads and one ground are connected with a screwdriver. The pump should also be bonded in accordance with local codes, connecting the bare copper wire to the bonding lug.
After installation, the pump can be primed and programmed. Using a VS pump replaces any timeclock that you may be using with a standard pump. Variable speed pumps are programmed with the interface on top of the motor, or can be controlled with pool controllers.
Programming involves choosing motor speeds for different run times, enough to keep the pool clean, at the lowest possible speed. This can take some experimentation to set speeds for different tasks, as well as calculating turnover rate, to push all of the pool water through the filter at least once per day.
Benefits of Variable Speed Pool Pumps
- Lower energy consumption, as much as 75% less.
- Optimum flow rate for every pool system task.
- Permanent magnet motor runs cool to the touch.
- Quiet operation; much quieter than standard.
- Durability; magnet motors can last twice as long.